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Sample records for beam loading compensation

  1. Variable Current Transient Beam Loading Compensation

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, Zoltan D

    2000-10-25

    The energy spread caused by transients during beam turn-on can be reduced by suitable timing of the beam turn-on[1]. If the beam is injected when the no-load voltage reaches the desired loaded voltage, then the energy spread is about 10%. To eliminate this energy spread, one can amplitude or phase modulate the section input power for one fill time, so that when the beam is turned on, the no-load voltage equals the desired loaded voltage and from then on, the change in no-load voltage tracks the beam induced voltage. It is known that for a constant gradient (CG) structure, and amplitude variation of the form E(t) = a{sub 0} + (1 - a{sub 0}) t{sub p} will reduce the energy spread to zero for a current that is determined by a{sub 0}. When one uses rf modulation for transient beam loading compensation, the beam is injected a fill time after the rf has been turned on, and one is forced to throw away a section's worth of rf energy. In addition, it requires extra components which use up additional rf energy. This note describes transient beam loading compensation with variable current. It will show that it increases the rf energy to beam energy transfer efficiency.

  2. Beam loading compensation for the NLC low frequency linacs

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.; Miller, R.; Farkas, D.; Raubenheimer, T.; Tang, H.; Yeremian, D.

    1997-03-01

    The NLC low rf linacs are heavily loaded by a beam of about 130 ns in macropulse length (90 bunches) and a current up to 2.75 Amps. Beam loading voltage generates a large energy spread along the bunch train. This energy spread is critical for lattice design and, if not properly compensated, induces emittance growth and in turn lowers the luminosity of the machine. In this paper, the authors study the {Delta}F and {Delta}T beam loading compensation techniques for the NLC low rf linacs. They will apply these methods to the NLC low rf linacs to demonstrate the efficacy of these methods. Finally, they discuss a hybrid {Delta}T + {Delta}F method to improve the efficiency of beam loading compensation.

  3. Beam loading compensation with variable group velocity

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, Z.D.

    1992-08-01

    Consider a section with linearly variable group velocity and a beam pulse shorter than the section fill time. Choose the current amplitude so that the gradient of the last bunch equals the gradient of the first bunch. For beam pulses less than about 15% of fill time, the voltage deviation during the beam pulse is small, but as the pulse width increases the voltage deviation also increases. We show that by decreasing the output to input group velocity ratio, we can reduce the first order voltage deviation, and that we can remove the remaining second-order voltage deviation by linearly decreasing the section input power by a small amount starting at beam injection time. This way we can increase the beam pulse width to more than half the fill time, and thereby increase the RF to beam energy transfer efficiency and the luminosity without increasing the voltage deviation.

  4. CLIC Main Linac Beam-Loading Compensation by Drive Beam Phase Modulation

    CERN Document Server

    Corsini, R; Syratchev, I V

    1999-01-01

    The CLIC final focus momentum acceptance of ± 0.5 % limits the bunch-to-bunch energy variation in the main beam to less than ± 0.1 %, since the estimated single-bunch contribution is ± 0.4 %. On the other hand, a relatively high beam-loading of the main accelerating structures (about 16 %) is unavoidable in order to optimize the RF-to-beam efficiency. Therefore, a compensation method is needed to reduce the resulting bunch-to-bunch energy spread of the main beam. Up to now, it has been planned to obtain the RF pulse shape needed for compensation by means of a charge ramp in the drive beam pulse. On the other hand, the use of constant-current drive beam pulses would make the design and operation of the drive beam injector considerably simpler. In this paper we present a possible solution adapted to the CLIC two-beam scheme with constant-current pulses, based on phase modulation of the drive beam bunches.

  5. Narrowband beam loading compensation in the Fermilab Main Injector accelerating cavities

    Energy Technology Data Exchange (ETDEWEB)

    Joseph E. Dey; John S. Reid and James Steimel

    2001-07-12

    A narrowband beam loading compensation system was installed for the Main Injector Accelerating Cavities. This feedback operates solely on the fundamental resonant mode of the cavity. This paper describes modifications to the high level Radio Frequency system required to make the system operational. These modifications decreased the effect of steady-state beam loading by a factor of 10 and improved the reliability of paraphasing for coalescing.

  6. Beam loading

    CERN Document Server

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  7. Transient beam-loading model and compensation in Compact Linear Collider main linac

    CERN Document Server

    Kononenko, O

    2011-01-01

    A new model to compensate for the transient beam loading in the CLIC main linac is developed. It takes into account the CLIC specific power generation scheme and the exact 3D geometry of the accelerating structure including couplers. A new method of calculating unloaded and loaded voltages during the transient is proposed and a dedicated optimization scheme of the rf pulse to compensate the transient beam-loading effect is presented. It is demonstrated that the 0.03% limit on the rms relative bunch-to-bunch energy spread in the main beam after acceleration can be reached. The optimization technique has been used to increase the rf to beam efficiency while preserving the CLIC requirements and to compensate for the energy spread caused by the Balakin-Novokhatski-Smirnov damping and transient process in the subharmonic buncher. Effects of charge jitters in the drive and main beams are studied. It is shown that within the 0.1% CLIC specification limit on the rms spread in beams charge the energy spread is not sig...

  8. Study on transient beam loading compensation for China ADS proton linac injector II

    CERN Document Server

    Gao, Zheng; Wang, Xian-Wu; Chang, Wei; Zhang, Rui-Feng; Zhu, Zheng-Long; Zhang, Sheng-Hu; Chen, Qi; Powers, Tom

    2016-01-01

    Significant transient beam loading effects were observed during beam commissioning tests of prototype II of the injector for the Accelerator Driven Sub-critical (ADS) system, which took place at the Institute of Modern Physics, Chinese Academy of Sciences, between October and December 2014. During these tests experiments were performed with CW operation of the cavities with pulsed beam current, and the system was configured to make use of a prototype digital low level radio frequency (LLRF) controller. The system was originally operated in pulsed mode with a simple PID feedback control algorithm, which was not able to maintain the desired gradient regulation during pulsed 10 mA beam operations. A unique simple transient beam loading compensation method which made use of a combination of PI feedback and feedforward control algorithm was implemented in order to significantly reduce the beam induced transient effect in the cavity gradients. The superconducting cavity field variation was reduced to less than 1.7%...

  9. Study on transient beam loading compensation for China ADS proton linac injector II

    Science.gov (United States)

    Gao, Zheng; He, Yuan; Wang, Xian-Wu; Chang, Wei; Zhang, Rui-Feng; Zhu, Zheng-Long; Zhang, Sheng-Hu; Chen, Qi; Powers, Tom

    2016-05-01

    Significant transient beam loading effects were observed during beam commissioning tests of prototype II of the injector for the accelerator driven sub-critical (ADS) system, which took place at the Institute of Modern Physics, Chinese Academy of Sciences, between October and December 2014. During these tests experiments were performed with continuous wave (CW) operation of the cavities with pulsed beam current, and the system was configured to make use of a prototype digital low level radio frequency (LLRF) controller. The system was originally operated in pulsed mode with a simple proportional plus integral and deviation (PID) feedback control algorithm, which was not able to maintain the desired gradient regulation during pulsed 10 mA beam operations. A unique simple transient beam loading compensation method which made use of a combination of proportional and integral (PI) feedback and feedforward control algorithm was implemented in order to significantly reduce the beam induced transient effect in the cavity gradients. The superconducting cavity field variation was reduced to less than 1.7% after turning on this control algorithm. The design and experimental results of this system are presented in this paper. Supported by National Natural Science Foundation of China (91426303, 11525523)

  10. Multiharmonic rf feedforward system for compensation of beam loading and periodic transient effects in magnetic-alloy cavities of a proton synchrotron

    Science.gov (United States)

    Tamura, Fumihiko; Ohmori, Chihiro; Yamamoto, Masanobu; Yoshii, Masahito; Schnase, Alexander; Nomura, Masahiro; Toda, Makoto; Shimada, Taihei; Hasegawa, Katsushi; Hara, Keigo

    2013-05-01

    Beam loading compensation is a key for acceleration of a high intensity proton beam in the main ring (MR) of the Japan Proton Accelerator Research Complex (J-PARC). Magnetic alloy loaded rf cavities with a Q value of 22 are used to achieve high accelerating voltages without a tuning bias loop. The cavity is driven by a single harmonic (h=9) rf signal while the cavity frequency response also covers the neighbor harmonics (h=8,10). Therefore the wake voltage induced by the high intensity beam consists of the three harmonics, h=8,9,10. The beam loading of neighbor harmonics is the source of periodic transient effects and a possible source of coupled bunch instabilities. In the article, we analyze the wake voltage induced by the high intensity beam. We employ the rf feedforward method to compensate the beam loading of these three harmonics (h=8,9,10). The full-digital multiharmonic feedforward system was developed for the MR. We describe the system architecture and the commissioning methodology of the feedforward patterns. The commissioning of the feedforward system has been performed by using high intensity beams with 1.0×1014 proteins per pulse. The impedance seen by the beam is successfully reduced and the longitudinal oscillations due to the beam loading are reduced. By the beam loading compensation, stable high power beam operation is achieved. We also report the reduction of the momentum loss during the debunching process for the slow extraction by the feedforward.

  11. An analytical approach for beam loading compensation and excitation of maximum cavity field gradient in a coupled cavity-waveguide system

    Science.gov (United States)

    Kelisani, M. Dayyani; Doebert, S.; Aslaninejad, M.

    2016-08-01

    The critical process of beam loading compensation in high intensity accelerators brings under control the undesired effect of the beam induced fields to the accelerating structures. A new analytical approach for optimizing standing wave accelerating structures is found which is hugely fast and agrees very well with simulations. A perturbative analysis of cavity and waveguide excitation based on the Bethe theorem and normal mode expansion is developed to compensate the beam loading effect and excite the maximum field gradient in the cavity. The method provides the optimum values for the coupling factor and the cavity detuning. While the approach is very accurate and agrees well with simulation software, it massively shortens the calculation time compared with the simulation software.

  12. An analytical approach for beam loading compensation and excitation of maximum cavity field gradient in a coupled cavity-waveguide system

    Energy Technology Data Exchange (ETDEWEB)

    Kelisani, M. Dayyani, E-mail: mdayyani@cern.ch [Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); European Organization for Nuclear Research (CERN), BE Department, CH-1211 Geneva 23 (Switzerland); Doebert, S. [European Organization for Nuclear Research (CERN), BE Department, CH-1211 Geneva 23 (Switzerland); Aslaninejad, M. [Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

    2016-08-21

    The critical process of beam loading compensation in high intensity accelerators brings under control the undesired effect of the beam induced fields to the accelerating structures. A new analytical approach for optimizing standing wave accelerating structures is found which is hugely fast and agrees very well with simulations. A perturbative analysis of cavity and waveguide excitation based on the Bethe theorem and normal mode expansion is developed to compensate the beam loading effect and excite the maximum field gradient in the cavity. The method provides the optimum values for the coupling factor and the cavity detuning. While the approach is very accurate and agrees well with simulation software, it massively shortens the calculation time compared with the simulation software.

  13. Successful Beam-Beam Tuneshift Compensation

    Energy Technology Data Exchange (ETDEWEB)

    Bishofberger, Kip Aaron [Univ. of California, Los Angeles, CA (United States)

    2005-01-01

    The performance of synchrotron colliders has been limited by the beam-beam limit, a maximum tuneshift that colliding bunches could sustain. Due to bunch-to-bunch tune variation and intra-bunch tune spread, larger tuneshifts produce severe emittance growth. Breaking through this constraint has been viewed as impossible for several decades. This dissertation introduces the physics of ultra-relativistic synchrotrons and low-energy electron beams, with emphasis placed on the limits of the Tevatron and the needs of a tuneshift-compensation device. A detailed analysis of the Tevatron Electron Lens (TEL) is given, comparing theoretical models to experimental data whenever possible. Finally, results of Tevatron operations with inclusion of the TEL are presented and analyzed. It is shown that the TEL provides a way to shatter the previously inescapable beam-beam limit.

  14. Digitally compensated beam current transformer

    CERN Document Server

    Kesselman, Martin

    2005-01-01

    The Spallation Neutron Source (SNS) is being built by a collaboration of six laboratories. Beam current monitors (BCMs) will be used to record the current of H-minus and H-plus beams ranging from 15 mA (tune-up in the Front End and Linac) to over 60A fully accumulated in the Ring and dumped to the load as a single pulse in the Ring to Beam Target (RTBT). The time structure of these beams ranges from 645ns "mini" bunches at the 1.05 MHz ring revolution rate, to an overall 1 ms long macro-pulse. The requirements for the BCMs will depend upon their location within the system. The need to measure individual mini-pulses, examine the characteristics of the chopper edge, as well as the longer average current pulse of the macropulse, or long duration pulses during Linac tuning place wide requirements upon the response of current transformers. To obtain the desired accuracy and resolution, current transformers must have less than 1 ns rise time and droops of 0.1 %/ms. This places a significant design burden on the cur...

  15. Compensator configurations for load currents' symmetrization

    Science.gov (United States)

    Rusinaru, D.; Manescu, L. G.; Dinu, R. C.

    2016-02-01

    This paper approaches aspects regarding the mitigation effects of asymmetries in 3-phase 3-wire networks. The measure consisting in connecting of load current symmetrization devices at the load coupling point is presented. A time-variation of compensators parameters is determined as a function of the time-recorded electrical values. The general sizing principle of the load current symmetrization reactive components is based on a simple equivalent model of the unbalanced 3-phase loads. By using these compensators a certain control of the power components transits is ensured in the network. The control is based on the variations laws of the compensators parameters as functions of the recorded electrical values: [B] = [T]·[M]. The link between compensator parameters and measured values is ensured by a transformation matrix [T] for each operation conditions of the supply network. Additional conditions for improving of energy and efficiency performance of the compensator are considered: i.e. reactive power compensation. The compensator sizing algorithm was implemented into a MATLAB environment software, which generate the time-evolution of the parameters of load current symmetrization device. The input data of application takes into account time-recording of the electrical values. By using the compensator sizing software, some results were achieved for the case of a consumer connected at 20 kV busbar of a distribution substation, during 24 hours measurement session. Even the sizing of the compensators aimed some additional network operation aspects (power factor correction) correlated with the total or major load symmetrizations, the harmonics aspects of the network values were neglected.

  16. LHC beam-beam compensation using wires and electron lenses

    CERN Document Server

    Dorda, U; Shiltsev, V; Zimmermann, F

    2007-01-01

    We present weak-strong simulation results for a possible application of current-carrying wires and electron lenses to compensate the LHC long-range and head-on beambeam interaction, respectively, for nominal and PACMAN bunches. We show that these measures have the potential to considerably increase the beam-beam limit, allowing for a corresponding increase in peak luminosity.

  17. A NEW HYSTERESIS COMPENSATION METHOD FOR LOAD CELLS

    Institute of Scientific and Technical Information of China (English)

    ZhuZijian; ChenRenwen

    2002-01-01

    A new hysteresis compensation method is presented.After analyzing the characteristics of strain-gage based load cells under loading & unloading conditions, mathe-matical models are established.A solution to compensate the hysteresis of the load cell by the experiments.It is shown that the method is reliable and can effectively re-duce the hysteresis.

  18. Study on space charge compensation in negative hydrogen ion beam.

    Science.gov (United States)

    Zhang, A L; Peng, S X; Ren, H T; Zhang, T; Zhang, J F; Xu, Y; Guo, Z Y; Chen, J E

    2016-02-01

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H(+) beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H(-) beam from a 2.45 GHz microwave driven H(-) ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  19. Study on space charge compensation in negative hydrogen ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, A. L.; Chen, J. E. [University of Chinese Academy of Sciences, Beijing 100049 (China); State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China); Peng, S. X., E-mail: sxpeng@pku.edu.cn; Ren, H. T.; Zhang, T.; Zhang, J. F.; Xu, Y.; Guo, Z. Y. [State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871 (China)

    2016-02-15

    Negative hydrogen ion beam can be compensated by the trapping of ions into the beam potential. When the beam propagates through a neutral gas, these ions arise due to gas ionization by the beam ions. However, the high neutral gas pressure may cause serious negative hydrogen ion beam loss, while low neutral gas pressure may lead to ion-ion instability and decompensation. To better understand the space charge compensation processes within a negative hydrogen beam, experimental study and numerical simulation were carried out at Peking University (PKU). The simulation code for negative hydrogen ion beam is improved from a 2D particle-in-cell-Monte Carlo collision code which has been successfully applied to H{sup +} beam compensated with Ar gas. Impacts among ions, electrons, and neutral gases in negative hydrogen beam compensation processes are carefully treated. The results of the beam simulations were compared with current and emittance measurements of an H{sup −} beam from a 2.45 GHz microwave driven H{sup −} ion source in PKU. Compensation gas was injected directly into the beam transport region to modify the space charge compensation degree. The experimental results were in good agreement with the simulation results.

  20. Generation of compensated ion beams from source with oscillating electrons

    CERN Document Server

    Borisko, V N; Yunakov, N N

    2000-01-01

    The generation of compensated ion beams from electrically unsymmetrical reflecting discharge was investigated.The spatial location of a compensation zone,the optimal values of operating gas pressures P=(0.8/1) centre dot 10 sup - sup 4 Torr and potential difference between cathodes DELTA U = 80B were determined.The way to control the current compensation degree of the extracted ion beam a several to 100% was found.

  1. Compensating tune spread induced by space charge in bunched beams

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, V.; Wang, G.

    2015-05-03

    The effects of space charge play a significant role in modern-day accelerators, frequently constraining the beam parameters attainable in an accelerator or in an accelerator chain. They also can limit the luminosity of hadron colliders operating either at low energies or with sub-TeV high-brightness hadron beams. The latter is applied for strongly cooled proton and ion beams in eRHIC – the proposed future electron-ion collider at Brookhaven National Laboratory. Using an appropriate electron beam would compensate both the tune shift and the tune spread in the hadron beam in a coasting beam. But these methods cannot compensate space charge tune spread in a bunched hadron beam. In this paper we propose and evaluate a novel idea of using a co-propagating electron bunch with mismatched longitudinal velocity to compensate the space charge induced tune-shift and tune spread.

  2. Energy compensation of slow extracted beams with RF acceleration

    Science.gov (United States)

    Fujimoto, Tetsuya; Souda, Hikaru; Torikoshi, Masami; Kanai, Tatsuaki; Yamada, Satoru; Noda, Koji

    2016-03-01

    In a conventional carbon-ion radiotherapy facility, a carbon-ion beam is typically accelerated up to an optimum energy, slowly extracted from a synchrotron ring by a resonant slow extraction method, and ultimately delivered to a patient through a beam-delivery system. At Japan's Gunma University, a method employing slow-beam extraction along with beam-acceleration has been adopted. This method slightly alters the extracted-beam's energy owing to the acceleration component of the process, which subsequently results in a residual-range variation of approximately 2 mm in water-equivalent length. However, this range variation does not disturb a distal dose distribution with broad-beam methods such as the single beam-wobbling method. With the pencil-beam 3D scanning method, however, such a range variation disturbs a distal dose distribution because the variation is comparable to slice thickness. Therefore, for pencil-beam 3D scanning, an energy compensation method for a slow extracted beam is proposed in this paper. This method can compensate for the aforementioned energy variances by controlling net energy losses through a rotatable energy absorber set fixed between the synchrotron exit channel and the isocenter. Experimental results demonstrate that beam energies can be maintained constant, as originally hypothesized. Moreover, energy-absorber positions were found to be significantly enhanced by optimizing beam optics for reducing beam-size growth by implementation of the multiple-scattering effect option.

  3. Emittance Compensation in a Flat Beam RF Photoinjector

    Science.gov (United States)

    Rosenzweig, J. B.; Anderson, S.; Colby, E.; Serafini, L.

    1997-05-01

    The beam dynamics of a flat beam rf photoinjector, which is intended to produce asymmetric emittances for linear collider applications, are analyzed, by both analytical and computational methods. The analytical model is a generalization of the recently developed theory of emittance compensation in round beams(L.Serafini, and J.B. Rosenzweig, submitted to Physical Review E.), in which a new mode of laminar flow beam dynamics, the invariant envelope, is found to give the ideal conditions for emittance minimization. Three-dimensional rf and beam dynamics simulations are used to iluminate the analytical results. abstract.

  4. The role of space charge compensation for ion beam extraction and ion beam transport (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Spädtke, Peter, E-mail: p.spaedtke@gsi.de [GSI Helmholtzzentrum für Schwerionenforschung GmbH (Germany)

    2014-02-15

    Depending on the specific type of ion source, the ion beam is extracted either from an electrode surface or from a plasma. There is always an interface between the (almost) space charge compensated ion source plasma, and the extraction region in which the full space charge is influencing the ion beam itself. After extraction, the ion beam is to be transported towards an accelerating structure in most cases. For lower intensities, this transport can be done without space charge compensation. However, if space charge is not negligible, the positive charge of the ion beam will attract electrons, which will compensate the space charge, at least partially. The final degree of Space Charge Compensation (SCC) will depend on different properties, like the ratio of generation rate of secondary particles and their loss rate, or the fact whether the ion beam is pulsed or continuous. In sections of the beam line, where the ion beam is drifting, a pure electrostatic plasma will develop, whereas in magnetic elements, these space charge compensating electrons become magnetized. The transport section will provide a series of different plasma conditions with different properties. Different measurement tools to investigate the degree of space charge compensation will be described, as well as computational methods for the simulation of ion beams with partial space charge compensation.

  5. Low level RF systems for synchrotrons part II: High Intensity. Compensation of the beam induced effects

    CERN Document Server

    Baudrenghien, P

    2005-01-01

    The high intensity regime is reached when the voltage induced by the beam in the RF cavities is of an amplitude comparable to the desired accelerating voltage. In steady state this beam loading can be compensated by providing extra RF power. Transient beam loading occurs at injection or in the presence of a beam intensity that is not uniform around the ring. The transients are periodic at the revolution frequency. Without correction transient beam loading can be very harmful: The stable phase and bucket area will not be equal for all bunches. Strong beam loading often goes in pair with longitudinal instabilities because the RF cavities are a large contributor to the total ring impedance. The low level systems that reduce the effect of the transient beam loading will also increase the threshold intensity of the longitudinal instability caused by the cavity impedance at the fundamental RF frequency. Four classic methods are presented here: Feedforward, RF feedback, long delay feedback and bunch by bunch feedbac...

  6. Functionally graded piezoelectric cantilever beam under load

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Z.F.; Chen, Y. [Beijing Jiaotong University, School of Civil Engineering, Beijing (China)

    2004-12-01

    In the present paper, the problem of a functionally graded piezoelectric cantilever beam subjected to different loadings is studied. The piezoelectric beam is characterized by continuously graded properties for one elastic parameter and the material density. A pair of stress and induction functions in the form of polynomials is proposed and determined. Based on these functions, a set of analytical solutions for the beam subjected to different loadings is obtained. As particular cases, series of solutions for some canonical problems can be directly obtained from the solutions of the present paper, such as for the problems of a piezoelectric cantilever beam with constant body force or without body forces, etc. (orig.)

  7. Compensation techniques in NIRS proton beam radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Akanuma, A. (Univ. of Tokyo, Japan); Majima, H.; Furukawa, S.

    1982-09-01

    Proton beam has the dose distribution advantage in radiation therapy, although it has little advantage in biological effects. One of the best advantages is its sharp fall off of dose after the peak. With proton beam, therefore, the dose can be given just to cover a target volume and potentially no dose is delivered thereafter in the beam direction. To utilize this advantage, bolus techniques in conjunction with CT scanning are employed in NIRS proton beam radiation therapy planning. A patient receives CT scanning first so that the target volume can be clearly marked and the radiation direction and fixation method can be determined. At the same time bolus dimensions are calculated. The bolus frames are made with dental paraffin sheets according to the dimensions. The paraffin frame is replaced with dental resin. Alginate (a dental impression material with favorable physical density and skin surface contact) is now employed for the bolus material. With fixation device and bolus on, which are constructed individually, the patient receives CT scanning again prior to a proton beam treatment in order to prove the devices are suitable. Alginate has to be poured into the frame right before each treatments. Further investigations are required to find better bolus materials and easier construction methods.

  8. Contributions to the mini-workshop on beam-beam compensation in the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, V.

    1998-02-01

    The purpose of the Workshop was to assay the current understanding of compensation of the beam-beam effects in the Tevatron with use of low-energy high-current electron beam, relevant accelerator technology, along with other novel techniques of the compensation and previous attempts. About 30 scientists representing seven institutions from four countries--FNAL, SLAC, BNL, Novosibirsk, CERN, and Dubna were in attendance. Twenty one talks were presented. The event gave firm ground for wider collaboration on experimental test of the compensation at the Tevatron collider. This report consists of vugraphs of talks given at the meeting.

  9. Space charge compensation in low energy proton beams

    CERN Document Server

    Ismail, A B; Uriot, D; Pichoff, N

    2004-01-01

    High power accelerators are being studied for several projects including accelerator driven neutron or neutrino sources. The low energy part of these facilities has to be carefully optimized to match the beam requirements of the higher energy parts. In this low energy part, the space charge self force, induced by a high intensity beam, has to be carefully managed. This nonlinear force can generate a high irreversible emittance growth of the beam. To reduce space charge effects, neutralization of the beam charge can be done by capturing some particles of the ionised residual gas in the vacuum chamber. This space charge compensation (SCC) regime complicates the dynamic study. Modelling the beam behaviour in such regime would be a significant contribution to the development of high intensity accelerators. Numerical and experimental study of SCC is in progress on the Saclay High Intensity Proton Injector. Experimental measurements and 2D/3D simulations of proton beam SCC will be presented.

  10. Applications of electron lenses: scraping of high-power beams, beam-beam compensation, and nonlinear optics

    Energy Technology Data Exchange (ETDEWEB)

    Stancari, Giulio

    2014-09-11

    Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Hollow electron beam collimation and halo control were studied as an option to complement the collimation system for the upgrades of the Large Hadron Collider (LHC) at CERN; a conceptual design was recently completed. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compensation in LHC luminosity upgrade scenarios with small crossing angles. At Fermilab, we are planning to install an electron lens in the Integrable Optics Test Accelerator (IOTA, a 40-m ring for 150-MeV electrons) as one of the proof-of-principle implementations of nonlinear integrable optics to achieve large tune spreads and more stable beams without loss of dynamic aperture.

  11. Status of head-on beam-beam compensation in RHIC

    CERN Document Server

    Fischer, W; Anerella, M; Blaskiewicz, M; Bruno, D; Costanzo, M; Dawson, W C; Gassner, D M; Gu, X; Gupta, R C; Hamdi, K; Hock, J; Hoff, L T; Hulsart, R; Jain, A K; Lambiase, R; Luo, Y; Mapes, M; Marone, A; Michnoff, R; Miller, T A; Minty, M; Montag, C; Muratore, J; Nemesure, S; Phillips, D; Pikin, A I; Plate, S R; Rosas, P; Snydstrup, L; Tan, Y; Theisen, C; Thieberger, P; Tuozzolo, J; Wanderer, P; White, S M; Zhang, W

    2014-01-01

    In polarized proton operation, the performance of the Relativistic Heavy Ion Collider (RHIC) is limited by the head-on beam-beam effect. To overcome this limitation, two electron lenses are under commissioning. We give an overview of head-on beam-beam compensation in general and in the specific design for RHIC, which is based on electron lenses. The status of installation and commissioning are presented along with plans for the future.

  12. Electron Beam Energy Compensation by Controlling RF Pulse Shape

    CERN Document Server

    Kii, T; Kusukame, K; Masuda, K; Nakai, Y; Ohgaki, H; Yamazaki, T; Yoshikawa, K; Zen, H

    2005-01-01

    We have studied on improvement of electron beam macropulse properties from a thermionic RF gun. Though a thermionic RF gun has many salient features, there is a serious problem that back-bombardment effect worsens quality of the beam. To reduce beam energy degradation by this effect, we tried to feed non-flat RF power into the gun. As a result, we successfully obtained about 1.5 times longer macropulse and two times larger total charge per macropulse. On the other hand, we calculated transient evolution of RF power considering non-constant beam loading. The beam loading is evaluated from time evolution of cathode temperature, by use of one dimensional heat conduction model and electron trajectories' calculations by a particle simulation code. Then we found good agreement between the experimental and calculation results. Furthermore, with the same way, we studied the electron beam output dependence on the cathode radius.

  13. A Novel Control algorithm based DSTATCOM for Load Compensation

    Science.gov (United States)

    R, Sreejith; Pindoriya, Naran M.; Srinivasan, Babji

    2015-11-01

    Distribution Static Compensator (DSTATCOM) has been used as a custom power device for voltage regulation and load compensation in the distribution system. Controlling the switching angle has been the biggest challenge in DSTATCOM. Till date, Proportional Integral (PI) controller is widely used in practice for load compensation due to its simplicity and ability. However, PI Controller fails to perform satisfactorily under parameters variations, nonlinearities, etc. making it very challenging to arrive at best/optimal tuning values for different operating conditions. Fuzzy logic and neural network based controllers require extensive training and perform better under limited perturbations. Model predictive control (MPC) is a powerful control strategy, used in the petrochemical industry and its application has been spread to different fields. MPC can handle various constraints, incorporate system nonlinearities and utilizes the multivariate/univariate model information to provide an optimal control strategy. Though it finds its application extensively in chemical engineering, its utility in power systems is limited due to the high computational effort which is incompatible with the high sampling frequency in these systems. In this paper, we propose a DSTATCOM based on Finite Control Set Model Predictive Control (FCS-MPC) with Instantaneous Symmetrical Component Theory (ISCT) based reference current extraction is proposed for load compensation and Unity Power Factor (UPF) action in current control mode. The proposed controller performance is evaluated for a 3 phase, 3 wire, 415 V, 50 Hz distribution system in MATLAB Simulink which demonstrates its applicability in real life situations.

  14. Applications of electron lenses: scraping of high-power beams, beam-beam compensation, and nonlinear optics

    CERN Document Server

    Stancari, Giulio

    2014-01-01

    Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam. Electron lenses were used in the Fermilab Tevatron collider for bunch-by-bunch compensation of long-range beam-beam tune shifts, for removal of uncaptured particles in the abort gap, for preliminary experiments on head-on beam-beam compensation, and for the demonstration of halo scraping with hollow electron beams. Electron lenses for beam-beam compensation are being commissioned in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Hollow electron beam collimation and halo control were studied as an option to complement the collimation system for the upgrades of the Large Hadron Collider (LHC) at CERN; a conceptual design was recently completed. Because of their electric charge and the absence of materials close to the proton beam, electron lenses may also provide an alternative to wires for long-range beam-beam compens...

  15. Testing Long-Range Beam-Beam Compensation for the LHC Luminosity Upgrade

    CERN Document Server

    Rijoff, T L

    2012-01-01

    The performance of the Large Hadron Collider (LHC) at CERN and its minimum crossing angle are limited by the effect of long-range beam-beam collisions. A wire compensators can mitigate part of the long-range effects and may allow for smaller crossing angles, or higher beam intensity. A prototype long-range wire compensator could be installed in the LHC by 2014/15. Since the originally reserved position for such a wire compensator is not available for this first step, we explore other possible options. Our investigations consider various longitudinal and transverse locations, different wire shapes, different optics configurations and several crossing angles between the two colliding beams. Simulations are carried out with the weak-strong code BBtrack. New postprocessing tools are introduced to analyse tune footprints and particle stability. In particular, a new method for the Lyapunov coefficient calculation is implemented. Submitted as "Tesi di laurea" at the University of Milano, 2012.

  16. Voltage Unbalance Compensation with Smart Three-phase Loads

    DEFF Research Database (Denmark)

    Douglass, Philip; Trintis, Ionut; Munk-Nielsen, Stig

    2016-01-01

    This paper describes the design, proof-of-concept simulations and laboratory test of an algorithm for controlling active front-end rectifiers to reduce voltage unbalance. Using inputs of RMS voltage, the rectifier controller allocates load unevenly on its 3 phases to compensate for voltage unbala...... is caused by asymmetrical loads. These results suggest that the optimal algorithm to reduce system unbalance depends on which system parameter is most important: phase-neutral voltage unbalance, phase-phase voltage unbalance, or current unbalance....

  17. The effects of betatron phase advances on beam-beam and its compensation in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y.; Fischer, W.; Gu, X.; Tepikian, S.; Trbojevic, D.

    2011-03-28

    In this article we perform simulation studies to investigate the effects of betatron phase advances between the beam-beam interaction points on half-integer resonance driving term, second order chromaticty and dynamic aperture in RHIC. The betatron phase advances are adjusted with artificial matrices inserted in the middle of arcs. The lattices for the 2011 RHIC polarized proton (p-p) run and 2010 RHIC Au-Au runs are used in this study. We also scan the betatron phase advances between IP8 and the electron lens for the proposed Blue ring lattice with head-on beam-beam compensation.

  18. Method for compensating bellows pressure loads while accommodating thermal deformations

    Energy Technology Data Exchange (ETDEWEB)

    Woodle, M.H.

    1985-01-01

    Many metal bellows are used on storage ring vacuum chambers. They allow the ring to accommodate deformations associated with alignment, mechanical assembly and thermal expansion. The NSLS has two such electron storage rings, the vuv ring and the x-ray ring. Both rings utilize a number of welded metal bellows within the ring and at every beam port. There are provisions for 16 beam ports on the vuv and 28 ports in the x-ray ring. At each of these locations the bellows are acted on by an external pressure of 1 atmosphere, which causes a 520 lb reaction at the vacuum chamber beam port and at the beamline flange downstream of the bellows. The use of rigid tie rods across the bellows flanges to support this load is troublesome because most storage ring vacuum chambers are baked in situ to achieve high internal vacuum. Significant forces can develop on components if thermal deformation is restrained and damage could occur.

  19. RF Wire Compensator of Long-Range Beam-Beam Effects

    CERN Document Server

    Dorda, U; Kroyer, T; Zimmermann, F

    2008-01-01

    The dynamic aperture of the proton beam circulating in the Large Hadron Collider (LHC) is expected to be limited by up to 120 long-range beam-beam encounters. In order to perfectly compensate the LHC long-range beambeam effect for nominal as well as for so-called "PACMAN" bunches, i.e. bunches at the start or end of a bunch train, the strength of a wire compensator should be adjusted for each bunch individually. Here an RF-based compensator is proposed as a practical solution for the PACMAN compensation. We show that this approach also allows relaxing the power and precision requirements compared with those of a pulsed DC device, to a level within the state-of-the-art of RF technology. Furthermore it permits the use of a passive circulator in the tunnel close to the beam and thus a significant reduction of the transmission line length and of the associated multiple reflections. Simulations of dynamic aperture and emittance growth, issues related to RF phase noise, and first experimental results from laborator...

  20. The damped oscillating propagation of the compensating self-accelerating beams

    CERN Document Server

    Liu, Wei-Wei; Yu, Pan-Pan; Wang, Hao-wei; Wang, Zi-qiang; Li, Yin-Mei

    2016-01-01

    We report a new form of compensating accelerating beam generated by amplitude modulation of the symmetric Airy beam (SAB) caustics with an exponential apodization mask. Our numerical study manifests that the compensating beam is with one main-lobe beam structure and can maintain the mean-intensity invariant both in the free space and loss media. Specially, the beam inherits the beamlets structure from the SAB and owns a novel damped oscillating propagation property. We also conduct a comparative study of its propagation property with that of the Airy beam theoretically. And by altering the signs of 2D masks, the main lobe of the compensating beam can be modulated to orientate in four different quadrants flexibly. The proposed compensating accelerating beam is anticipated to get special applications in particle manipulation or plasmas regions.

  1. Space Charge Compensation in the Linac4 Low Energy Beam Transport Line with Negative Hydrogen Ions

    CERN Document Server

    Valerio-Lizarraga, C; Leon-Monzon, I; Lettry, J; Midttun, O; Scrivens, R

    2014-01-01

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Tranport (LEBT) using the package IBSimu1, which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H- beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  2. Robust Control for Static Loading of Electro-hydraulic Load Simulator with Friction Compensation

    Institute of Scientific and Technical Information of China (English)

    YAO Jianyong; JIAO Zongxia; YAO Bin

    2012-01-01

    Load simulator is a key test equipment for aircraft actuation systems in hardware-in-the-loop-simulation.Static loading is an essential function of the load simulator and widely used in the static/dynamic stiffness test of aircraft actuation systems.The tracking performance of the static loading is studied in this paper.Firstly,the nonlinear mathematical models of the hydraulic load simulator are derived,and the feedback linearization method is employed to construct a feed-forward controller to improve the force tracking performance.Considering the effect of the friction,a LuGre model based friction compensation is synthesized,in which the unmeasurable state is estimated by a dual state observer via a controlled learning mechanism to guarantee that the estimation is bounded.The modeling errors are attenuated by a well-designed robust controller with a control accuracy measured by a design parameter.Employing the dual state observer is to capture the different effects of the unmeasured state and hence can improve the friction compensation accuracy.The tracking performance is summarized by a derived theorem.Experimental results are also obtained to verify the high performance nature of the proposed control strategy.

  3. Long-Range And Head-On Beam-Beam Compensation Studies in RHIC With Lessons for the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, W.; Luo, Y.; Abreu, N.; Calaga, R.; Montag, C.; Robert-Demolaize, G.; /Brookhaven; Dorda, U.; Koutchouk, J.P.; Sterbini, G.; Zimmermann, F.; /CERN; Kim, H.J.; Sen, T.; Shiltsev, V.; Valishev, A.; /Fermilab; Qiang, J.; /LBL, Berkeley; Kabel, A.; /SLAC

    2011-11-28

    Long-range as well as head-on beam-beam effects are expected to limit the LHC performance with design parameters. They are are also important consideration for the LHC upgrades. To mitigate long-range effects, current carrying wires parallel to the beam were proposed. Two such wires are installed in RHIC where they allow studying the effect of strong long-range beam-beam effects, as well as the compensation of a single long-range interaction. The tests provide benchmark data for simulations and analytical treatments. Electron lenses were proposed for both RHIC and the LHC to reduce the head-on beam-beam effect. We present the experimental long-range beam-beam program at RHIC and report on head-on compensations studies based on simulations.

  4. The E-lens test bench for RHIC beam-beam compensation

    Energy Technology Data Exchange (ETDEWEB)

    Gu X.; Altinbas, F.Z.; Aronson, J.; Beebe, E. et al

    2012-05-20

    To compensate for the beam-beam effects from the proton-proton interactions at IP6 and IP8 in the Relativistic Heavy Ion Collider (RHIC), we are fabricating two electron lenses that we plan to install at RHIC IR10. Before installing the e-lenses, we are setting-up the e-lens test bench to test the electron gun, collector, GS1 coil, modulator, partial control system, some instrumentation, and the application software. Some e-lens power supplies, the electronics for current measurement will also be qualified on test bench. The test bench also was designed for measuring the properties of the cathode and the profile of the beam. In this paper, we introduce the layout and elements of the e-lens test bench; and we discuss its present status towards the end of this paper.

  5. An Alternative High Luminosity LHC with Flat Optics and Long-Range Beam-Beam Compensation

    CERN Document Server

    AUTHOR|(CDS)2070952; Valishev, Aleksander; Shatilov, Dmitry

    2015-01-01

    In the baseline scenario of the High-Luminosity LHC (HL-LHC), the geometric loss of luminosity in the two high luminosity experiments due to collisions with a large crossing angle is recovered by tilting the bunches in the interaction region with the use of crab cavities. A possible backup scenario would rely on a reduced crossing angle together with flat optics (with different horizontal and vertical β∗ values) for the preservation of luminosity performance. However, the reduction of crossing angle coupled with the flat optics significantly enhances the strength of long-range beam-beam interactions. This paper discusses the possibility to mitigate the long-range beam-beam effects by current bearing wire compensators (or e-lens). We develop a new HL-LHC parameter list and analyze it in terms of integrated luminosity performance as compared to the baseline. Further, we evaluate the operational scenarios using numerical simulations of single-particle dynamics with beam-beam effects.

  6. An Alternative High Luminosity LHC with Flat Optics and Long-Range Beam-Beam Compensation

    Energy Technology Data Exchange (ETDEWEB)

    Fartoukh, Stephane [CERN; Valishev, Alexander [Fermilab; Shatilov, Dmitry [BINP, Novosibirsk

    2015-06-01

    In the baseline scenario of the High-Luminosity LHC (HL-LHC), the geometric loss of luminosity in the two high luminosity experiments due to collisions with a large crossing angle is recovered by tilting the bunches in the interaction region with the use of crab cavities. A possible backup scenario would rely on a reduced crossing angle together with flat optics (with different horizontal and vertical $\\beta^{\\ast}$values) for the preservation of luminosity performance. However, the reduction of crossing angle coupled with the flat optics significantly enhances the strength of long-range beam-beam interactions. This paper discusses the possibility to mitigate the long-range beam-beam effects by current bearing wire compensators (or e-lens). We develop a new HL-LHC parameter list and analyze it in terms of integrated luminosity performance as compared to the baseline. Further, we evaluate the operational scenarios using numerical simulations of single-particle dynamics with beam-beam effects.

  7. Symplectic Modeling of Beam Loading in Electromagnetic Cavities

    CERN Document Server

    Abell, Dan T; Webb, Stephen D

    2016-01-01

    Simulating beam loading in radiofrequency accelerating structures is critical for understanding higher-order mode effects on beam dynamics, such as beam break-up instability in energy recovery linacs. Full wave simulations of beam loading in radiofrequency structures are computationally expensive, while reduced models can ignore essential physics and can be difficult to generalize. We present a self-consistent algorithm derived from the least-action principle which can model an arbitrary number of cavity eigenmodes and with a generic beam distribution.

  8. Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions.

    Science.gov (United States)

    Valerio-Lizarraga, Cristhian A; Lallement, Jean-Baptiste; Leon-Monzon, Ildefonso; Lettry, Jacques; Midttun, Øystein; Scrivens, Richard

    2014-02-01

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H(-) beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  9. Space charge compensation in the Linac4 low energy beam transport line with negative hydrogen ions

    Energy Technology Data Exchange (ETDEWEB)

    Valerio-Lizarraga, Cristhian A., E-mail: cristhian.alfonso.valerio.lizarraga@cern.ch [CERN, Geneva (Switzerland); Departamento de Investigación en Física, Universidad de Sonora, Hermosillo (Mexico); Lallement, Jean-Baptiste; Lettry, Jacques; Scrivens, Richard [CERN, Geneva (Switzerland); Leon-Monzon, Ildefonso [Facultad de Ciencias Fisico-Matematicas, Universidad Autónoma de Sinaloa, Culiacan (Mexico); Midttun, Øystein [CERN, Geneva (Switzerland); University of Oslo, Oslo (Norway)

    2014-02-15

    The space charge effect of low energy, unbunched ion beams can be compensated by the trapping of ions or electrons into the beam potential. This has been studied for the 45 keV negative hydrogen ion beam in the CERN Linac4 Low Energy Beam Transport using the package IBSimu [T. Kalvas et al., Rev. Sci. Instrum. 81, 02B703 (2010)], which allows the space charge calculation of the particle trajectories. The results of the beam simulations will be compared to emittance measurements of an H{sup −} beam at the CERN Linac4 3 MeV test stand, where the injection of hydrogen gas directly into the beam transport region has been used to modify the space charge compensation degree.

  10. Compensation of non-ideal beam splitter polarization distortion effect in Michelson interferometer

    Science.gov (United States)

    Liu, Yeng-Cheng; Lo, Yu-Lung; Liao, Chia-Chi

    2016-02-01

    A composite optical structure consisting of two quarter-wave plates and a single half-wave plate is proposed for compensating for the polarization distortion induced by a non-ideal beam splitter in a Michelson interferometer. In the proposed approach, the optimal orientations of the optical components within the polarization compensator are determined using a genetic algorithm (GA) such that the beam splitter can be treated as a free-space medium and modeled using a unit Mueller matrix accordingly. Two implementations of the proposed polarization controller are presented. In the first case, the compensator is placed in the output arm of Michelson interferometer such that the state of polarization of the interfered output light is equal to that of the input light. However, in this configuration, the polarization effects induced by the beam splitter in the two arms of the interferometer structure cannot be separately addressed. Consequently, in the second case, compensator structures are placed in the Michelson interferometer for compensation on both the scanning and reference beams. The practical feasibility of the proposed approach is introduced by considering a Mueller polarization-sensitive (PS) optical coherence tomography (OCT) structure with three polarization controllers in the input, reference and sample arms, respectively. In general, the results presented in this study show that the proposed polarization controller provides an effective and experimentally-straightforward means of compensating for the polarization distortion effects induced by the non-ideal beam splitters in Michelson interferometers and Mueller PS-OCT structures.

  11. On compensating tune spread induced by space charge in bunched beams

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko V. N.; Wang, G.

    2014-05-09

    Space charge effects play significant role in modern-day accelerators. These effects frequently constrain attainable beam parameters in an accelerator, or, in an accelerator chain. They also could limit the luminosity of hadron colliders operating either at low energies or with a sub-TeV high brightness hadron beams. The latter is applied for strongly cooled proton and ion beams in eRHIC – the proposed future electron-ion collider at Brookhaven National Laboratory. A number of schemes for compensating space charge effects in a coasting (e.g. continuous) hadron beam were proposed and some of them had been tested. Using a proper transverse profile of the electron beam (or plasma column) for a coasting beam would compensate both the tune shift and the tune spread in the hadron beam. But all of these methods do not address the issue of tune spread compensation of a bunched hadron beam, e.g. the tune shift dependence on the longitudinal position inside the bunch. In this paper we propose and evaluate a novel idea of using a co-propagating electron bunch with miss-matched longitudinal velocity to compensate the space charge induced tune-shift and tune spread. We present a number of practical examples of such system.

  12. A viscoelastic orthotropic Timoshenko beam subjected to general transverse loading

    Directory of Open Access Journals (Sweden)

    Adámek V.

    2008-12-01

    Full Text Available The investigation of lateral vibrations of a simply supported thin beam is the aim of this work. The analytical solution of the problem is derived based on the approximate Timoshenko beam theory for a general continuous loading acting on the upper beam face over the whole beam width and perpendicular to the beam axis. The material of the beam studied is assumed linear orthotropic viscoelastic. The generalized standard viscoelastic solid is chosen for representing of viscoelastic beam behaviour. Final system of partial integro-differential equations is solved by the standard method of integral transforms and resulting relations describing beam deflection, slope of the beam and corresponding stress and strain components are presented. Moreover, the derivation of final functions of beam deflection and slope of the beam for a specific impulse loading is presented and analytical results are compared with results obtained using numerical simulation in 2D (FEM. This confrontation shows very good agreement between results obtained. Furthermore, it was shown that the measure of agreement depends not only on the beam geometry.

  13. On Compensating Tune Spread Induced by Space Charge in Bunched Beams

    CERN Document Server

    Litvinenko, Vladimir N

    2014-01-01

    Space charge effects play significant role in modern-day accelerators. These effects frequently constrain attainable beam parameters in an accelerator - or - in an accelerator chain. They also could limit the luminosity of hadron colliders operating either at low energies or with a sub-TeV high brightness hadron beams. A number of schemes for compensating space charge effects in a coasting (e.g. continuous) hadron beam were proposed and some of them had been tested. But all of these methods do not address the issue of tune spread compensation of a bunched hadron beam, e.g. the tune shift dependence on the longitudinal position inside the bunch. In this paper we propose and evaluate a novel idea of using a co-propagating electron bunch with miss-matched longitudinal velocity to compensate the space charge induced tune-shift and tune spread. We present a number of practical examples of such system.

  14. Lightweight Aggregate Concrete Beams. Load-bearing Capacity

    DEFF Research Database (Denmark)

    Larsen, Henning; Goltermann, Per; Ingholt, N.U.

    1997-01-01

    This paper deals with the load-bearing capacity of reinforced beams made of lightweight aggregate concrete with open structure and documents formulas for the moment capacity as well as the shear force capacity.......This paper deals with the load-bearing capacity of reinforced beams made of lightweight aggregate concrete with open structure and documents formulas for the moment capacity as well as the shear force capacity....

  15. Impact load mitigation in sandwich beams using local resonators

    CERN Document Server

    Sharma, B

    2015-01-01

    Dynamic response of sandwich beams with resonators embedded in the cores subjected to impact loads is studied. Using finite element models the effectiveness of various local resonator frequencies under a given impact load is compared to the behavior of an equivalent mass beam. It is shown that addition of appropriately chosen local resonators into the sandwich beam is an effective method of improving its flexural bending behavior under impact loads. The effect of a given local resonance frequency under different impact load durations is also studied. It is demonstrated that the choice of appropriate local resonance frequency depends on the impact duration. Further, by performing transverse impact experiments, the finite element models are verified and the advantage of using internal resonators under impact loading conditions is demonstrated.

  16. TRANSIENT BEAM LOADING EFFECTS IN RF SYSTEMS IN JLEIC

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haipeng [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Guo, Jiquan [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Rimmer, Robert A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Wang, Shaoheng [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-05-01

    The pulsed electron bunch trains generated from the Continuous Electron Beam Accelerator Facility (CEBAF) linac to inject into the proposed Jefferson Lab Electron Ion Collider (JLEIC) e-ring will produce transient beam loading effects in the Superconducting Radio Frequency (SRF) systems that, if not mitigated, could cause unacceptably large beam energy deviation in the injection capture, or exceed the energy acceptance of CEBAF’s recirculating arcs. In the electron storage ring, the beam abort or ion clearing gaps or uneven bucket filling can cause large beam phase transients in the (S)RF cavity control systems and even beam loss due to Robinson instability. We have first analysed the beam stability criteria in steady state and estimated the transient effect in Feedforward and Feedback RF controls. Initial analytical models for these effects are shown for the design of the JLEIC e-ring from 3GeV to 12GeV.

  17. Approach to unbalance power active compensation under linear load unbalances and fundamental voltage asymmetries

    Energy Technology Data Exchange (ETDEWEB)

    Segui-Chilet, S.; Gimeno-Sales, F.J.; Orts, S.; Alcaniz, M.; Masot, R. [Instituto de Tecnologia Electrica - Grupo de Tecnologia Electronica, Universidad Politecnica de Valencia, Camino de Vera 14, 46022 Valencia (Spain); Garcera, G.; Figueres, E. [Departamento de Ingenieria Electronica, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)

    2007-09-15

    This paper proposes a new definition of the unbalance power that allows the selective compensation of inefficiencies caused by linear loads by means of a three-phase shunt active power compensator (APC). Symmetrical components of current and voltage are used to evaluate the unbalance power in these systems and to define the compensating currents. The instantaneous power flows with unbalanced linear loads connected to a three-phase electrical system are analyzed following the normal procedure used for the quantification of the reactive power. Equations to calculate the unbalance power and the effective apparent power are obtained from the analysis of the instantaneous power flows. The output currents of the selective APC are defined using the instantaneous unbalance power approach. Power quantities and APC compensating current are defined for IEEE Std. 1459 and for the instantaneous unbalance power approach. Two examples are used to compare the power quantities and the APC operation. The main effects of unbalanced linear load and of fundamental voltage asymmetries are analyzed. Simulations of a shunt APC emphasize the advantages of the calculation of the compensating currents based on the proposed instantaneous unbalance power approach. A comparison with the results obtained by calculation of the compensating currents based on IEEE Std. 1459 is carried out. A new power factor is also defined and compared with other conventional definitions. (author)

  18. Compensation for Adolescents’ School Mental Load by Physical Activity on Weekend Days

    Directory of Open Access Journals (Sweden)

    Michal Kudláček

    2016-03-01

    Full Text Available Introduction and objective: Increasing mental load and inadequate stress management significantly affect the efficiency, success and safety of the educational/working process in adolescents. The objective of this study is to determine the extent that adolescents compensate for their school mental load by physical activity (PA on weekend days and, thus, to contribute to the objective measurement of mental load in natural working conditions. Methods: A cross-sectional study was conducted between September 2013 and April 2014. A set of different methods was employed—self-administered questionnaire (IPAQ-long questionnaire, objective measurements—pedometers, and accelerometers (ActiTrainers. They was distributed to 548 students from 17 high schools. Participants’ mental load was assessed based on the difference between PA intensity and/or physical inactivity and heart rate range. Results: The participants with the highest mental load during school lessons do not compensate for this load by PA on weekend days. Conclusions: Adolescents need to be encouraged to be aware of their subjective mental load and to intentionally compensate for this load by PA on weekend days. It is necessary to support the process of adopting habits by sufficient physical literacy of students, as well as teachers, and by changes in the school program.

  19. Coupling Dynamics Interlip Coordination in Lower Lip Load Compensation

    Science.gov (United States)

    van Lieshout, Pascal; Neufeld, Chris

    2014-01-01

    Purpose: To study the effects of lower lip loading on lower and upper lip movements and their coordination to test predictions on coupling dynamics derived from studies in limb control. Method: Movement data were acquired using electromagnetic midsagittal articulography under 4 conditions: (a) without restrictions, serving as a baseline; (b) with…

  20. Compensation of beam-beam and space-charge effects: experience to-date and near-future opportunities

    CERN Document Server

    Shiltsev, V

    2014-01-01

    Beam-beam interactions and space-charge effects belong to the category of the most long-standing issues in beam physics, and even today, after several decades of very active exploration and development of counter-measures, they still pose the most profound limitations on performance of accelerator facilities. In this brief review we consider past experience in active compensation of these effects and possible new schemes for further exploration in near-future, in particular, within the framework of the electron-ion collider R&D.

  1. Active and passive compensation of APPLE II-introduced multipole errors through beam-based measurement

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Ting-Yi; Huang, Szu-Jung; Fu, Huang-Wen; Chang, Ho-Ping; Chang, Cheng-Hsiang [National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Hwang, Ching-Shiang [National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Department of Electrophysics, National Chiao Tung University, Hsinchu 30050, Taiwan (China)

    2016-08-01

    The effect of an APPLE II-type elliptically polarized undulator (EPU) on the beam dynamics were investigated using active and passive methods. To reduce the tune shift and improve the injection efficiency, dynamic multipole errors were compensated using L-shaped iron shims, which resulted in stable top-up operation for a minimum gap. The skew quadrupole error was compensated using a multipole corrector, which was located downstream of the EPU for minimizing betatron coupling, and it ensured the enhancement of the synchrotron radiation brightness. The investigation methods, a numerical simulation algorithm, a multipole error correction method, and the beam-based measurement results are discussed.

  2. Effect of ion compensation of the beam space charge on gyrotron operation

    Energy Technology Data Exchange (ETDEWEB)

    Fokin, A. P.; Glyavin, M. Yu. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod 603950 (Russian Federation); Nusinovich, G. S. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States)

    2015-04-15

    In gyrotrons, the coherent radiation of electromagnetic waves takes place when the cyclotron resonance condition between the wave frequency and the electron cyclotron frequency or its harmonic holds. The voltage depression caused by the beam space charge field changes the relativistic cyclotron frequency and, hence, can play an important role in the beam-wave interaction process. In long pulse and continuous-wave regimes, the beam space charge field can be partially compensated by the ions, which appear due to the beam impact ionization of neutral molecules of residual gases in the interaction space. In the present paper, the role of this ion compensation of the beam space charge on the interaction efficiency is analyzed. We also analyze the effect of the electron velocity spread on the limiting currents and discuss some effects restricting the ion-to-beam electron density ratio in the saturation stage. It is shown that the effect of the ion compensation on the voltage depression caused by the beam space charge field can cause significant changes in the efficiency of gyrotron operation and, in some cases, even result in the break of oscillations.

  3. Double beam near-infrared spectrometer for compensation of background water absorption and instrumental drift in intensity

    Institute of Scientific and Technical Information of China (English)

    CHANG Min; PENG Dan; XU Ke-xin

    2007-01-01

    A double beam near-infrared spectrometer is developed to compensate the water absorption and instrumental drift in intensity. The spectrometer maybe used for both single and double beam measurements, and the two operation modes are compared. The results show that the double beam technique eliminates instrumental drift in the single beam measurement and therefore the stability of the system increases by more than 20%. The compensation of the double beam system on water absorption is verified by the measurement of fat content in milk. The results show that the spectrum data based on double beam mode get better calibration model and lower prediction error than traditional single beam mode.

  4. Voltage Unbalance Compensation with Smart Three-phase Loads

    DEFF Research Database (Denmark)

    Douglass, Philip; Trintis, Ionut; Munk-Nielsen, Stig

    2016-01-01

    voltage, but it does not reduce the negative sequence voltage. The controller that uses phase-phase voltage as input eliminates negative sequence voltage, and reduces voltage deviations from the average to approximately half their initial value. Current unbalance is reduced when the voltage unbalance...... is caused by asymmetrical loads. These results suggest that the optimal algorithm to reduce system unbalance depends on which system parameter is most important: phase-neutral voltage unbalance, phase-phase voltage unbalance, or current unbalance....

  5. A statistical approach to motion compensated cone-beam

    DEFF Research Database (Denmark)

    Lyksborg, Mark; Hansen, Mads Fogtmann; Larsen, Rasmus

    One of the problems arising in radiotherapy planning is the quality of CT planning data. In the following attention is giving to the cone-beam scanning geometry where reconstruction of a 3D volume based on 2D projections, using the classic Feldkamp-Davis-Kress (FDK) algorithm requires a large...

  6. A Statistical Approach to Motion Compensated Cone Beam Reconstruction

    DEFF Research Database (Denmark)

    Lyksborg, Mark; Hansen, Mads Fogtmann; Larsen, Rasmus

    2010-01-01

    One of the problems arising in radiotherapy planning is the quality of CT planning data. In the following attention is giving to the cone-beam scanning geometry where reconstruction of a 3D volume based on 2D projections, using the classic Feldkamp-Davis-Kress (FDK) algorithm requires a large...

  7. Compensation of the long-range beam-beam interactions as a path towards new configurations for the High Luminosity LHC

    CERN Document Server

    AUTHOR|(SzGeCERN)390904; Papaphilippou, Yannis; Shatilov, Dmitry

    2015-01-01

    Colliding bunch trains in a circular collider demands a certain crossing angle in order to separate the two beams transversely after the collision. The magnitude of this crossing angle is a complicated function of the bunch charge, the number of long-range beam-beam interactions, of β* and type of optics (flat or round), and possible compensation or additive effects between several low-β insertions in the ring depending on the orientation of the crossing plane at each interaction point. About 15 years ago, the use of current bearing wires was proposed at CERN in order to mitigate the longrange beam-beam effects, therefore offering the possibility to minimize the crossing angle with all the beneficial effects this might have: on the luminosity performance by reducing the need for crab-cavities or lowering their voltage, on the required aperture of the final focus magnets, on the strength of the orbit corrector involved in the crossing bumps, and finally on the heat load and radiation dose deposited in the fi...

  8. Photovoltaic power converter system with a controller configured to actively compensate load harmonics

    Science.gov (United States)

    de Rooij, Michael Andrew; Steigerwald, Robert Louis; Delgado, Eladio Clemente

    2008-12-16

    Photovoltaic power converter system including a controller configured to reduce load harmonics is provided. The system comprises a photovoltaic array and an inverter electrically coupled to the array to generate an output current for energizing a load connected to the inverter and to a mains grid supply voltage. The system further comprises a controller including a first circuit coupled to receive a load current to measure a harmonic current in the load current. The controller includes a second circuit to generate a fundamental reference drawn by the load. The controller further includes a third circuit for combining the measured harmonic current and the fundamental reference to generate a command output signal for generating the output current for energizing the load connected to the inverter. The photovoltaic system may be configured to compensate harmonic currents that may be drawn by the load.

  9. Application of Load Compensation in Voltage Controllers of Large Generators in the Polish Power Grid

    Directory of Open Access Journals (Sweden)

    Bogdan Sobczak

    2014-03-01

    Full Text Available The Automatic Voltage Regulator normally controls the generator stator terminal voltage. Load compensation is used to control the voltage which is representative of the voltage at a point either within or external to the generator. In the Polish Power Grid (PPG compensation is ready to use in every AVR of a large generator, but it is utilized only in the case of generators operating at the same medium voltage buses. It is similar as in most European Power Grids. The compensator regulating the voltage at a point beyond the machine terminals has significant advantages in comparison to the slower secondary Voltage and Reactive Power Control System (ARNE1. The compensation stiffens the EHV grid, which leads to improved voltage quality in the distribution grid. This effect may be particularly important in the context of the dynamic development of wind and solar energy.

  10. New diagnostic technique for Zeeman-compensated atomic beam slowing: technique and results

    NARCIS (Netherlands)

    Molenaar, P.A.; Straten, P. van der; Heideman, H.G.M.; Metcalf, H.

    2001-01-01

    We have developed a new diagnostic tool for the study of Zeeman-compensated slowing of an alkali atomic beam. Our time-of-flight technique measures the longitudinal veloc- ity distribution of the slowed atoms with a resolution below the Doppler limit of 30 cm/s. Furthermore, it can map the position

  11. Integral Sliding Mode Control Strategy of D-STATCOM for Unbalanced Load Compensation under Various Disturbances

    Directory of Open Access Journals (Sweden)

    Mingchao Xia

    2013-01-01

    Full Text Available Control strategies of D-STATCOM for unbalanced load compensation under internal and external disturbances were discussed. Linear control strategies do not have a satisfactory dynamic performance and become invalid under internal or external disturbances. To guarantee a good precision and robustness, a control strategy combining input-output feedback linearization technique with integral sliding mode control (ISMC method was applied to D-STATCOM for unbalanced load compensation. The strategy has features of simple structure and is easy to implement. A 10 MVar/10 kV D-STATCOM simulation system was built in PSCAD/EMTDC to verify the effectiveness and robustness of the control strategy proposed. Simulation results show that the control strategy can compensate reactive power and eliminate unbalance simultaneously under various disturbances.

  12. Partial loss compensation in dielectric-loaded plasmonic waveguides at near infra-red wavelengths

    DEFF Research Database (Denmark)

    Garcia, Cesar; Coello, Victor; Han, Zhanghua;

    2012-01-01

    We report on the fabrication and characterization of straight dielectric-loaded surface plasmon polaritons waveguides doped with lead-sulfide quantum dots as a near infra-red gain medium. A loss compensation of ~33% (an optical gain of ~143 cm^−1) was observed in the guided mode. The mode propaga...

  13. A cyclodissipativity characterization of power factor compensation of nonlinear loads under nonsinusoidal conditions

    NARCIS (Netherlands)

    del Puerto-Flores, D.; Ortega, R.; Scherpen, J. M. A.

    2012-01-01

    Recently, it has been established that power factor (PF) improvement for nonlinear loads with nonsinusoidal source voltage is equivalent to imposing the property of cyclodissipativity to the source terminals. Using this framework, the classical capacitor and inductor compensators were interpreted in

  14. Enhanced control strategy for MMC-based STATCOM for unbalanced load compensation

    DEFF Research Database (Denmark)

    Nieves, M.; Maza, J.M.; Mauricio, J.M.;

    2014-01-01

    as required for load unbalance compensation. This paper proposes an improved balancing strategy for the delta configuration to overcome this situation based on the injection of a third harmonic zero sequence current. Simulation results have proved the effectiveness of the proposal even where different...

  15. Ion Compensation for Space Charge in the Helical Electron Beams of Gyrotrons

    Science.gov (United States)

    Manuilov, V. N.; Semenov, V. E.

    2016-06-01

    We solve analytically the problem about ion compensation for the space charge of a helical electron beam in a gyrotron operated in the long-pulse regime. Elementary processes, which take place during ionization of residual gas in the tube under typical pressures of 10-6-10-7 mm Hg, are considered. It is shown that distribution of the space charge is affected mainly by the electrons of the initial beam and slow-moving ions produced by ionization of the residual gas. Steady-state density of ions in the operating space of the gyrotron after the end of the transitional processes is found, as well as the electron density profile in the channel of electron beam transportation. The results obtained allow us to evaluate the pitch-factor variations caused by partial compensations for the potential "sagging" in the gyrotron cavity, thus being useful for analysis of starting currents, efficiency, and mode competition in high-power gyrotrons.

  16. Field Test Result of 10MVA/20MJ SMES for Load Fluctuation Compensation

    Science.gov (United States)

    Nagaya, Shigeo; Nagata, Tatsuya; Hirano, Naoki; Tamada, Tsutomu; Nijo, Yoshio; Katagiri, Toshio; Yamane, Minoru

    SMES of the10,000kW for the power control in power system has been manufactured, and connected to a real power grid. In addition, innovative basic researches, for example, low cost converter, maintenance-free cryo-coolers, inter-locks system and so on, have also been developed. The SMES was installed in the metal rolling factory with hydro power plant. Field test has been carried out for load fluctuation compensation. SMES was able to compensate for the active power according to the fluctuating load, and confirm the situation with a smooth load change of 11kV bus of hydro power stations. In this paper, field test results are presented.

  17. Load beam unit replaceable inserts for dry coal extrusion pumps

    Science.gov (United States)

    Saunders, Timothy; Brady, John D.

    2012-11-13

    A track assembly for a particulate material extrusion pump according to an exemplary aspect of the present disclosure includes a link assembly with a roller bearing. An insert mounted to a load beam located such that the roller bearing contacts the insert.

  18. Compensating for the influence of the angular detuning of signal and reference beams on photocurrent in optical heterodyning

    Energy Technology Data Exchange (ETDEWEB)

    Abramian, A.S.; Kazarian, R.A.

    1980-01-01

    The fundamental possibility of compensating for the influence on photocurrent of the angular detuning between the plane fronts of signal and reference beams during optical mixing on the surface of a planar photodetector is demonstrated. Compensation is provided by rotating the plane of the detector relative to the incident emission; this rotation occurs in the plane of incidence of both beams, while the beams themselves remain stationary (detuned).

  19. Compensated gadolinium-loaded plastic scintillators for thermal neutron detection (and counting)

    Energy Technology Data Exchange (ETDEWEB)

    Dumazert, Jonathan; Coulon, Romain; Bertrand, Guillaume H. V.; Hamel, Matthieu; Sguerra, Fabien; Dehe-Pittance, Chrystele; Normand, Stephane [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 99 Gif-sur-Yvette, (France); Mechin, Laurence [CNRS, UCBN, Groupe de Recherche en Informatique, Image, Automatique et Instrumentation de Caen, 4050 Caen, (France)

    2015-07-01

    Plastic scintillator loading with gadolinium-rich organometallic complexes shows a high potential for the deployment of efficient and cost-effective neutron detectors. Due to the low-energy photon and electron signature of thermal neutron capture by gadolinium-155 and gadolinium-157, alternative treatment to Pulse Shape Discrimination has to be proposed in order to display a trustable count rate. This paper discloses the principle of a compensation method applied to a two-scintillator system: a detection scintillator interacts with photon radiation and is loaded with gadolinium organometallic compound to become a thermal neutron absorber, while a non-gadolinium loaded compensation scintillator solely interacts with the photon part of the incident radiation. Posterior to the nonlinear smoothing of the counting signals, a hypothesis test determines whether the resulting count rate after photon response compensation falls into statistical fluctuations or provides a robust image of a neutron activity. A laboratory prototype is tested under both photon and neutron irradiations, allowing us to investigate the performance of the overall compensation system in terms of neutron detection, especially with regards to a commercial helium-3 counter. The study reveals satisfactory results in terms of sensitivity and orientates future investigation toward promising axes. (authors)

  20. Load Torque Compensator for Model Predictive Direct Current Control in High Power PMSM Drive Systems

    DEFF Research Database (Denmark)

    Preindl, Matthias; Schaltz, Erik

    2011-01-01

    The widely used cascade speed and torque controllers have a limited control performance in most high power applications due to the low switching frequency of power electronic converters and the convenience to avoid speed overshoots and oscillations for lifetime considerations. Model Predictive...... to further improve dynamic behavior. It compensates the load torque influence on the speed control setting a feed forward torque reference value. The benefits are twice; the speed controller reaches the speed reference value without offsets which would need to be compensated by an integrator and a better...

  1. In situ magnetic compensation for potassium spin-exchange relaxation-free magnetometer considering probe beam pumping effect.

    Science.gov (United States)

    Fang, Jiancheng; Wang, Tao; Quan, Wei; Yuan, Heng; Zhang, Hong; Li, Yang; Zou, Sheng

    2014-06-01

    A novel method to compensate the residual magnetic field for an atomic magnetometer consisting of two perpendicular beams of polarizations was demonstrated in this paper. The method can realize magnetic compensation in the case where the pumping rate of the probe beam cannot be ignored. In the experiment, the probe beam is always linearly polarized, whereas, the probe beam contains a residual circular component due to the imperfection of the polarizer, which leads to the pumping effect of the probe beam. A simulation of the probe beam's optical rotation and pumping rate was demonstrated. At the optimized points, the wavelength of the probe beam was optimized to achieve the largest optical rotation. Although, there is a small circular component in the linearly polarized probe beam, the pumping rate of the probe beam was non-negligible at the optimized wavelength which if ignored would lead to inaccuracies in the magnetic field compensation. Therefore, the dynamic equation of spin evolution was solved by considering the pumping effect of the probe beam. Based on the quasi-static solution, a novel magnetic compensation method was proposed, which contains two main steps: (1) the non-pumping compensation and (2) the sequence compensation with a very specific sequence. After these two main steps, a three-axis in situ magnetic compensation was achieved. The compensation method was suitable to design closed-loop spin-exchange relaxation-free magnetometer. By a combination of the magnetic compensation and the optimization, the magnetic field sensitivity was approximately 4 fT/Hz(1/2), which was mainly dominated by the noise of the magnetic shield.

  2. Design of active temperature compensated composite free-free beam MEMS resonators in a standard process

    Science.gov (United States)

    Xereas, George; Chodavarapu, Vamsy P.

    2014-03-01

    Frequency references are used in almost every modern electronic device including mobile phones, personal computers, and scientific and medical instrumentation. With modern consumer mobile devices imposing stringent requirements of low cost, low complexity, compact system integration and low power consumption, there has been significant interest to develop batch-manufactured MEMS resonators. An important challenge for MEMS resonators is to match the frequency and temperature stability of quartz resonators. We present 1MHz and 20MHz temperature compensated Free-Free beam MEMS resonators developed using PolyMUMPS, which is a commercial multi-user process available from MEMSCAP. We introduce a novel temperature compensation technique that enables high frequency stability over a wide temperature range. We used three strategies: passive compensation by using a structural gold (Au) layer on the resonator, active compensation through using a heater element, and a Free-Free beam design that minimizes the effects of thermal mismatch between the vibrating structure and the substrate. Detailed electro-mechanical simulations were performed to evaluate the frequency response and Quality Factor (Q). Specifically, for the 20MHz device, a Q of 10,000 was obtained for the passive compensated design. Finite Element Modeling (FEM) simulations were used to evaluate the Temperature Coefficient of frequency (TCf) of the resonators between -50°C and 125°C which yielded +0.638 ppm/°C for the active compensated, compared to -1.66 ppm/°C for the passively compensated design and -8.48 ppm/°C for uncompensated design for the 20MHz device. Electro-thermo-mechanical simulations showed that the heater element was capable of increasing the temperature of the resonators by approximately 53°C with an applied voltage of 10V and power consumption of 8.42 mW.

  3. Space charge compensation on the low energy beam transport of Linac4

    CERN Document Server

    AUTHOR|(SzGeCERN)733270; Scrivens, Richard; Jesus Castillo, Santos

    Part of the upgrade program in the injector chains of the CERN accelerator complex is the replacement of the the proton accelerator Linac2 for the brand new Linac4 which will accelerate H$^-$ and its main goal is to increase the beam intensity in the next sections of the LHC accelerator chain. The Linac4 is now under commissioning and will use several ion sources to produce high intensity unbunched H$^-$ beams with different properties, and the low energy beam transport (LEBT) is the system in charge of match all these different beams to the Radio frequency quadrupole (RFQ). The space charge forces that spread the beam ions apart of each other and cause emittance growth limits the maximum intensity that can be transported in the LEBT, but the space charge of intense unbunched ion beams can be compensated by the generated ions by the impact ionization of the residual gas, which creates a source of secondary particles inside the beam pipe. For negative ion beams, the effect of the beam electric field is to ex...

  4. Transmission path phase compensation for gear monitoring under fluctuating load conditions

    Science.gov (United States)

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

    2006-10-01

    Vibration can be monitored under fluctuating load conditions if provision is made for taking into account the fluctuation in machine speed, the response amplitude modulation caused by the change in input force, and the amplitude and phase effects on the measured response from the transmission path. Methodologies have been developed to compensate for the effects of fluctuating speed and amplitude modulation. However, this article investigates the effect of the transmission path phase. This is discussed in terms of the effect this phase has on synchronous averaging. A new approach is presented to resolve the influence that the transmission path phase has on synchronous averaging. The approach is used for the experimental data measured on a helical gear test rig. A significant improvement in the rate of convergence was obtained by adopting the new approach which compensates for the phase shifting in the measured structural response. This contrasts with conventional synchronous averaging with order tracking which does not compensate for structural response phase shifting.

  5. Stud Reinforcement in Beam-Column Joints under Seismic Loads

    Science.gov (United States)

    Ibrahim, Hatem Hassan Ali

    Current codes recommend large amounts of shear reinforcement for reinforced concrete beam-column joints causing significant congestion. This research aims at investigating experimentally and numerically the efficiency of using studs with a head at each end in lieu of conventional closed hoops in reinforced concrete beam-column joints. The proposed reinforcement reduces congestion and ensures easier assembly of the reinforcing cage, saving labour cost and enhancing performance of the joint. Based on this research, a recommended arrangement and detailing of headed studs and their design for exterior beam-column joint are presented. The experimental investigation consisted of testing ten full-scale beam-column joint specimens under quasi-static cyclic loading. The specimens represented an exterior beam-column joint subassembly isolated at the points of contra-flexure from a typical multi-storey, multi-bay reinforced concrete frame. A test setup was developed to simulate the lateral inter-storey drift. The test parameters included: the type, arrangement and amount of shear reinforcement, the load history and rate of loading, and the amount of reinforcement for out-of-plane confinement of the joint. Envelopes of the hysteretic behaviour of the specimens and the joint deformation under shear stress are presented. The stiffness degradation, the strain levels in the joint reinforcement, the contribution of joint, beam, and column to the inter-storey drift, and the energy dissipation were compared. All the test specimens reinforced with headed studs in the joint achieved considerable enhancement in their behaviour under cyclic loads and exhibited a performance close to that of a joint reinforced with closed hoops and cross ties according to the code. All the specimens with adequate out-of-plane confinement had an equivalent behaviour compared with the code-based specimen and achieved a desirable mode of failure. Use of double-headed studs proved to be a viable option for

  6. Neural compensation, muscle load distribution and muscle function in control of biped models

    Science.gov (United States)

    Bavarian, B.

    Three aspects of the neuromuscular control of muscle actuators in biped movements were studied: neural compensation, muscle load distribution, and muscle function. A block diagram of a neural control circuit model of the control nervous system is presented. Based on this block diagram a circuit comprised of a dynamic compensator, an inverse plant, and pre-programmed reference trajectory generators is proposed for control of a general n-link biped model. This circuit is used to study the postural stability and point-to-point voluntary movement of a two-link planar biped with two pairs of muscle models. The muscle load distribution, relevant to functional electrical stimulation of paraplegic patients for restoration of limited motor function, is considered. A quantitative analysis of the local controllability of a two-link planar biped model incorporating six major muscles of the lower extremities is presented. A model of the muscle for the lower extremities is presented.

  7. Monte Carlo simulation of spectrum changes in a photon beam due to a brass compensator

    Energy Technology Data Exchange (ETDEWEB)

    Custidiano, E.R., E-mail: ernesto7661@gmail.com [Department of Physics, FaCENA, UNNE, Av., Libertad 5470, C.P.3400, Corrientes (Argentina); Valenzuela, M.R., E-mail: meraqval@gmail.com [Department of Physics, FaCENA, UNNE, Av., Libertad 5470, C.P.3400, Corrientes (Argentina); Dumont, J.L., E-mail: Joseluis.Dumont@elekta.com [Elekta CMS Software, St.Louis, MO (United States); McDonnell, J., E-mail: josemc@express.com.ar [Cumbres Institute, Riobamba 1745, C.P.2000, Rosario, Santa Fe (Argentina); Rene, L, E-mail: luismrene@gmail.com [Radiotherapy Center, Crespo 953, C.P.2000, Rosario, Santa Fe (Argentina); Rodriguez Aguirre, J.M., E-mail: juakcho@gmail.com [Department of Physics, FaCENA, UNNE, Av., Libertad 5470, C.P.3400, Corrientes (Argentina)

    2011-06-15

    Monte Carlo simulations were used to study the changes in the incident spectrum when a poly-energetic photon beam passes through a static brass compensator. The simulated photon beam spectrum was evaluated by comparing it against the incident spectra. We also discriminated the changes in the transmitted spectrum produced by each of the microscopic processes. (i.e. Rayleigh scattering, photoelectric effect, Compton scattering, and pair production). The results show that the relevant process in the energy range considered is the Compton Effect, as expected for composite materials of intermediate atomic number and energy range considered.

  8. Compensation of body shake errors in terahertz beam scanning single frequency holography for standoff personnel screening

    Science.gov (United States)

    Liu, Wei; Li, Chao; Sun, Zhao-Yang; Zhao, Yu; Wu, Shi-You; Fang, Guang-You

    2016-08-01

    In the terahertz (THz) band, the inherent shake of the human body may strongly impair the image quality of a beam scanning single frequency holography system for personnel screening. To realize accurate shake compensation in imaging processing, it is quite necessary to develop a high-precision measure system. However, in many cases, different parts of a human body may shake to different extents, resulting in greatly increasing the difficulty in conducting a reasonable measurement of body shake errors for image reconstruction. In this paper, a body shake error compensation algorithm based on the raw data is proposed. To analyze the effect of the body shake on the raw data, a model of echoed signal is rebuilt with considering both the beam scanning mode and the body shake. According to the rebuilt signal model, we derive the body shake error estimated method to compensate for the phase error. Simulation on the reconstruction of point targets with shake errors and proof-of-principle experiments on the human body in the 0.2-THz band are both performed to confirm the effectiveness of the body shake compensation algorithm proposed. Project supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. YYYJ-1123).

  9. Intelligent power factor compensation equipment of three phase low voltage loads

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An intelligent power factor correction scheme is presented for three phase low power factor loads. This new scheme is able to perform individual phase sensing of parameters by monitoring at all times to sense a change in system parameters and affects individual phase correction by applying the exact amount of reactive components needed for each phase, and can also reduce negative sequence current caused by the load to improve system balance. An optimization criterion is used for the proper calculation of reactive power steps in a power compensation installation of capacitor banks. The criterion is enabled by sampling measurements performed on the electrical plant examined within specific interval of time.

  10. Load monitoring and compensation strategies for guided-waves based structural health monitoring using piezoelectric transducers

    Science.gov (United States)

    Roy, Surajit; Ladpli, Purim; Chang, Fu-Kuo

    2015-09-01

    Accurate interpretation of in-situ piezoelectric sensor signals is a challenging task. This paper presents the development of a numerical compensation model based on physical insight to address the influence of structural loads on piezo-sensor signals. The model requires knowledge of in-situ strain and temperature distribution in a structure while acquiring piezoelectric sensor signals. The parameters of the numerical model are obtained using experiments on flat aluminum plate under uniaxial tensile loading. It is shown that the model parameters obtained experimentally can be used for different structures, and sensor layout. Furthermore, the combined effects of load and temperature on the piezo-sensor response are also investigated and it is observed that both of these factors have a coupled effect on the sensor signals. It is proposed to obtain compensation model parameters under a range of operating temperatures to address this coupling effect. An important outcome of this study is a new load monitoring concept using in-situ piezoelectric sensor signals to track changes in the load paths in a structure.

  11. Load monitoring and compensation strategies for guided-waves based structural health monitoring using piezoelectric transducers

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Surajit; Ladpli, Purim; Chang, Fu-Kuo

    2015-09-01

    Accurate interpretation of in-situ piezoelectric sensor signals is a challenging task. This article presents the development of a numerical compensation model based on physical insight to address the influence of structural loads on piezo-sensor signals. The model requires knowledge of in-situ strain and temperature distribution in a structure while acquiring sensor signals. The parameters of the numerical model are obtained using experiments on flat aluminum plate under uniaxial tensile loading. It is shown that the model parameters obtained experimentally can be used for different structures, and sensor layout. Furthermore, the combined effects of load and temperature on the piezo-sensor response are also investigated and it is observed that both of these factors have a coupled effect on the sensor signals. It is proposed to obtain compensation model parameters under a range of operating temperatures to address this coupling effect. An important outcome of this study is a new load monitoring concept using in-situ piezoelectric sensor signals to track changes in the load paths in a structure.

  12. Barrier Buckets and Transient Beam Loading in the SPS

    CERN Document Server

    Bohl, T; Garoby, R; Linnecar, Trevor Paul R; Shaposhnikova, Elena; Tückmantel, Joachim

    2003-01-01

    Using long bunches held in place by barrier buckets to overcome the limitations associated with peak density in high intensity bunched beams could be a promising scheme for increasing the luminosity of LHC. In the SPS at CERN an initial barrier bucket machine development(MD) study was done in 1999 to check the capabilities of 200 MHz thick barriers generated by the travelling wave system. A second experiment took place on 5th of August 2003 to examine high intensity effects. In this experiment a flat and stable long bunch of @ 3 µs bunch length was obtained and kept for more than 80 minutes without developing a significant line density modulation. However, strong beam loading effects were observed during the injection process, causing a coherent, non-negligible energy transfer from the beam to the RF cavities, and significant fraction of the injected beam was lost to a coasting beam background. The beam intensity that could be confined in between the barriers suffered emittance increase and was not high enou...

  13. Dynamic Response of Axially Loaded Euler-Bernoulli Beams

    DEFF Research Database (Denmark)

    Bayat, M.; Barari, Amin; Shahidi, M.

    2011-01-01

    The current research deals with application of a new analytical technique called Energy Balance Method (EBM) for a nonlinear problem. Energy Balance Method is used to obtain the analytical solution for nonlinear vibration behavior of Euler-Bernoulli beams subjected to axial loads. Analytical expr...... to the conventional methods, only one iteration leads to high accuracy of the solutions which are valid for a wide range of vibration amplitudes....

  14. Polarization beam combination technique for gain saturation effect compensation in high-energy systems

    Science.gov (United States)

    Chen, Junchi; Peng, Yujie; Su, Hongpeng; Leng, Yuxin

    2016-06-01

    To compensate for the gain saturation effect in the high-energy laser amplifier, a modified polarization beam combination (PBC) method is introduced to reshape temporal waveform of the injected laser pulse to obtain a controlled high-energy laser pulse shape after amplification. One linearly polarized beam is divided into two orthogonal polarized beams, which spatially recombine together collinearly after propagating different optical paths with relative time delay in PBC structure. The obtained beam with polarization direction being rotated by the following half wave plate is divided and combined again to reform a new beam in another modified polarization beam structure. The reformed beam is injected into three cascaded laser amplifiers. The amplified pulse shape can be controlled by the incident pulse shape and amplifier gain, which is agreeable to the simulation by the Frank-Nodvik equations. Based on the simple method, the various temporal waveform of output pulse with tunable 7 to 20 ns pulse duration can be obtained without interferometric fringes.

  15. Evaluation and Compensation of Detector Solenoid Effects on Disrupted Beam in the ILC 14 mrad Extraction Line

    Energy Technology Data Exchange (ETDEWEB)

    Toprek, Dragan; /VINCA Inst. Nucl. Sci., Belgrade; Nosochkov, Yuri; /SLAC

    2008-12-18

    This paper presents calculations of detector solenoid effects on disrupted primary beam in the ILC 14 mrad extraction line. Particle tracking simulations are performed for evaluation of primary beam loss along the line as well as of beam distribution and polarization at Compton Interaction Point. The calculations are done both without and with solenoid compensation. The results are obtained for the baseline ILC energy of 500 GeV center-of-mass and three options of beam parameters.

  16. Simulation study on the emittance compensation of off-axis emitted beam in RF photoinjector

    Science.gov (United States)

    Huang, Rui-Xuan; Mitchell, Chad; Jia, Qi-Ka; Papadopoulos, Christos; Sannibale, Fernando

    2016-11-01

    To make full use of the photocathode material and improve its quantum efficiency lifetime, it can be necessary to operate the laser away from the cathode center in photoinjectors. In RF guns, the off-axis emitted beam will see a time-dependent RF effect, which would generate a significant growth in transverse emittance. It has been demonstrated that such an emittance growth can be almost completely compensated by orienting the beam on a proper orbit in the downstream RF cavities along the injector [1]. In this paper we analyze in detail the simulation techniques used in reference [1] and the issues associated with them. The optimization of photoinjector systems involving off-axis beams is a challenging problem. To solve this problem, one needs advanced simulation tools including both genetic algorithms and an efficient algorithm for 3D space charge. In this paper, we report on simulation studies where the two codes ASTRA and IMPACT-T are used jointly to overcome these challenges, in order to optimize a system designed to compensate for the emittance growth in a beam emitted off axis. Supported by National Nature Science Foundation of China (11375199), and Chinese Scholarship Council

  17. A Space Charge Compensation Study of Low Energy Hydrogen Ion Beams

    CERN Document Server

    Ben-Ismail, A; Uriot, D; Pichoff, Nicolas

    2005-01-01

    High-power accelerators are being studied for several projects including accelerator driven neutron or neutrino sources. The low energy part of these facilities has to be carefully optimized to match the beam requirements of the higher energy parts. The complexity of high intensity beam dynamics in the low energy line is essentially due to the non-linear space charge effects. The PIC code CARTAGO* has been developed in order to simulate the beam transport at low energy including the temporal evolution effects of the space charge compensation. This paper relates the structure and the numerical methods of a 2D (r,z) new version of the code. The effects of the longitudinal space charge, the image charge and external 2D (r,z) magnetic field were included. The results of H+

  18. Improvements of the undulator spectral performance by compensating the backing beam deflection

    CERN Document Server

    Wang, C; Chang, L H; Chang, C H; Fan, T C; Bach, H; Blomqvist, I

    2002-01-01

    This study thoroughly examines how the backing beam deflection affects the undulator spectral performance. Reduction of the undulator spectral intensity owing to backing beam deflection is analytically evaluated based on plane-wave approximation. The results reveal that the amplitude and the slope of the backing beam deflection affect the undulator spectral performance. Provided is a novel figure-of-merit, rms of the regressed accumulated gap deviation, to determine the backing beam deflection budget. An example of a 3.9 m undulator supporting carriage mounted with 50-mm period length undulator magnet (U5) under a maximum magnetic loading of 5 metric tons at a minimum operating gap of 14 mm, is provided. Its mechanical features are first examined via 3D commercial finite element code ANSYS that concludes the backing beam deflection is influenced heavily by the rigidity of the undulator support frames. Examining the corresponding spectral performance shows that significantly diminishing the undulator spectral ...

  19. Compensated bismuth-loaded plastic scintillators for neutron detection using low-energy pseudo-spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dumazert, Jonathan, E-mail: jonathan.dumazert@cea.fr [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France); Coulon, Romain; Bertrand, Guillaume H.V.; Normand, Stéphane [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France); Méchin, Laurence [CNRS, UCBN, Groupe de Recherche en Informatique, Image, Automatique et Instrumentation de Caen, 14050 Caen (France); Hamel, Matthieu [CEA, LIST, Laboratoire Capteurs Architectures Electroniques, 91191 Gif-sur-Yvette (France)

    2016-05-21

    Gadolinium-covered modified plastic scintillators show a high potential for the deployment of cost-effective neutron detectors. Taking advantage of the low-energy photon and electron signature of thermal neutron captures in gadolinium-155 and gadolinium-157 however requires a background correction. In order to display a trustable rate, dual compensation schemes appear as an alternative to Pulse Shape Discrimination. This paper presents the application of such a compensation scheme to a two-bismuth loaded plastic scintillator system. A detection scintillator interacts with incident photon and fast neutron radiations and is covered with a gadolinium converter to become thermal neutron-sensitive as well. In the meantime, an identical compensation scintillator, covered with terbium, solely interacts with the photon and fast neutron part of incident radiations. After the acquisition and the treatment of the counting signals from both sensors, a hypothesis test determines whether the resulting count rate after subtraction falls into statistical fluctuations or provides a robust image of neutron activity. A laboratory prototype is tested under both photon and neutron radiations, allowing us to investigate the performance of the overall compensation system. The study reveals satisfactory results in terms of robustness to a cesium-137 background and in terms of sensitivity in presence of a californium-252 source.

  20. Compensated bismuth-loaded plastic scintillators for neutron detection using low-energy pseudo-spectroscopy

    Science.gov (United States)

    Dumazert, Jonathan; Coulon, Romain; Bertrand, Guillaume H. V.; Normand, Stéphane; Méchin, Laurence; Hamel, Matthieu

    2016-05-01

    Gadolinium-covered modified plastic scintillators show a high potential for the deployment of cost-effective neutron detectors. Taking advantage of the low-energy photon and electron signature of thermal neutron captures in gadolinium-155 and gadolinium-157 however requires a background correction. In order to display a trustable rate, dual compensation schemes appear as an alternative to Pulse Shape Discrimination. This paper presents the application of such a compensation scheme to a two-bismuth loaded plastic scintillator system. A detection scintillator interacts with incident photon and fast neutron radiations and is covered with a gadolinium converter to become thermal neutron-sensitive as well. In the meantime, an identical compensation scintillator, covered with terbium, solely interacts with the photon and fast neutron part of incident radiations. After the acquisition and the treatment of the counting signals from both sensors, a hypothesis test determines whether the resulting count rate after subtraction falls into statistical fluctuations or provides a robust image of neutron activity. A laboratory prototype is tested under both photon and neutron radiations, allowing us to investigate the performance of the overall compensation system. The study reveals satisfactory results in terms of robustness to a cesium-137 background and in terms of sensitivity in presence of a californium-252 source.

  1. Clinical evaluation of 4D PET motion compensation strategies for treatment verification in ion beam therapy

    Science.gov (United States)

    Gianoli, Chiara; Kurz, Christopher; Riboldi, Marco; Bauer, Julia; Fontana, Giulia; Baroni, Guido; Debus, Jürgen; Parodi, Katia

    2016-06-01

    A clinical trial named PROMETHEUS is currently ongoing for inoperable hepatocellular carcinoma (HCC) at the Heidelberg Ion Beam Therapy Center (HIT, Germany). In this framework, 4D PET-CT datasets are acquired shortly after the therapeutic treatment to compare the irradiation induced PET image with a Monte Carlo PET prediction resulting from the simulation of treatment delivery. The extremely low count statistics of this measured PET image represents a major limitation of this technique, especially in presence of target motion. The purpose of the study is to investigate two different 4D PET motion compensation strategies towards the recovery of the whole count statistics for improved image quality of the 4D PET-CT datasets for PET-based treatment verification. The well-known 4D-MLEM reconstruction algorithm, embedding the motion compensation in the reconstruction process of 4D PET sinograms, was compared to a recently proposed pre-reconstruction motion compensation strategy, which operates in sinogram domain by applying the motion compensation to the 4D PET sinograms. With reference to phantom and patient datasets, advantages and drawbacks of the two 4D PET motion compensation strategies were identified. The 4D-MLEM algorithm was strongly affected by inverse inconsistency of the motion model but demonstrated the capability to mitigate the noise-break-up effects. Conversely, the pre-reconstruction warping showed less sensitivity to inverse inconsistency but also more noise in the reconstructed images. The comparison was performed by relying on quantification of PET activity and ion range difference, typically yielding similar results. The study demonstrated that treatment verification of moving targets could be accomplished by relying on the whole count statistics image quality, as obtained from the application of 4D PET motion compensation strategies. In particular, the pre-reconstruction warping was shown to represent a promising choice when combined with intra

  2. Scattering-compensated cone beam x-ray luminescence computed tomography

    Science.gov (United States)

    Gao, Peng; Rong, Junyan; Pu, Huangsheng; Liu, Wenlei; Liao, Qimei; Lu, Hongbing

    2016-04-01

    X-ray luminescence computed tomography (XLCT) opens new possibilities to perform molecular imaging with x-ray. It is a dual modality imaging technique based on the principle that some nanophosphors can emit near-infrared (NIR) light when excited by x-rays. The x-ray scattering effect is a great issue in both CT and XLCT reconstruction. It has been shown that if the scattering effect compensated, the reconstruction average relative error can be reduced from 40% to 12% in the in the pencil beam XLCT. However, the scattering effect in the cone beam XLCT has not been proved. To verify and reduce the scattering effect, we proposed scattering-compensated cone beam x-ray luminescence computed tomography using an added leading to prevent the spare x-ray outside the irradiated phantom in order to decrease the scattering effect. Phantom experiments of two tubes filled with Y2O3:Eu3+ indicated that the proposed method could reduce the scattering by a degree of 30% and can reduce the location error from 1.8mm to 1.2mm. Hence, the proposed method was feasible to the general case and actual experiments and it is easy to implement.

  3. Real-time optical tracking for motion compensated irradiation with scanned particle beams at CNAO

    Energy Technology Data Exchange (ETDEWEB)

    Fattori, G., E-mail: giovanni.fattori@psi.ch [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Seregni, M. [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Pella, A. [Centro Nazionale di Adroterapia Oncologica (CNAO), Strada Campeggi 53, 27100 Pavia (Italy); Riboldi, M. [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Capasso, L. [Istituto Nazionale di Fisica Nucleare, Section of Torino, Torino 10125 (Italy); Donetti, M. [Centro Nazionale di Adroterapia Oncologica (CNAO), Strada Campeggi 53, 27100 Pavia (Italy); Istituto Nazionale di Fisica Nucleare, Section of Torino, Torino 10125 (Italy); Ciocca, M. [Centro Nazionale di Adroterapia Oncologica (CNAO), Strada Campeggi 53, 27100 Pavia (Italy); Giordanengo, S. [Istituto Nazionale di Fisica Nucleare, Section of Torino, Torino 10125 (Italy); Pullia, M. [Centro Nazionale di Adroterapia Oncologica (CNAO), Strada Campeggi 53, 27100 Pavia (Italy); Marchetto, F. [Istituto Nazionale di Fisica Nucleare, Section of Torino, Torino 10125 (Italy); Baroni, G. [Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Centro Nazionale di Adroterapia Oncologica (CNAO), Strada Campeggi 53, 27100 Pavia (Italy)

    2016-08-11

    Purpose: We describe the interface developed at the National Center for Oncological Hadrontherapy in Pavia to provide the dose delivery systems with real time respiratory motion information captured with an optical tracking system. An experimental study is presented to assess the technical feasibility of the implemented organ motion compensation framework, by analyzing the film response when irradiated with proton beams. Methods: The motion monitoring solution is based on a commercial hardware for motion capture running in-house developed software for respiratory signal processing. As part of the integration, the latency of data transmission to the dose delivery system was experimentally quantified and accounted for by signal time prediction. A respiratory breathing phantom is presented and used to test tumor tracking based either on the optical measurement of the target position or internal-external correlation models and beam gating, as driven by external surrogates. Beam tracking was tested considering the full target motion excursion (25×18 mm), whereas it is limited to 6×2 mm in the gating window. The different motion mitigation strategies were evaluated by comparing the experimental film responses with respect to static irradiation conditions. Dose inhomogeneity (IC) and conformity (CI) are provided as main indexes for dose quality assessment considering the irradiation in static condition as reference. Results: We measured 20.6 ms overall latency for motion signal processing. Dose measurements showed that beam tracking largely preserved dose homogeneity and conformity, showing maximal IC and CI variations limited to +0.10 and −0.01 with respect to the static reference. Gating resulted in slightly larger discrepancies (ΔIC=+0.20, ΔCI=−0.13) due to uncompensated residual motion in the gating window. Conclusions: The preliminary beam tracking and gating results verified the functionality of the prototypal solution for organ motion compensation based on

  4. Experimental Dynamic Analysis of Nonlinear Beams under Moving Loads

    Directory of Open Access Journals (Sweden)

    A. Bellino

    2012-01-01

    Full Text Available It is well known that nonlinear systems, as well as linear time-varying systems, are characterized by non-stationary response signals. In this sense, they both show natural frequencies that are not constant over time; this variation has however different origins: for a time-varying system the mass, and possibly the stiffness distributions, are changing over time, while for a nonlinear system the natural frequencies are amplitude-dependent. An interesting case of time-varying system occurs when analyzing the transit of a train over a railway bridge, easily simulated by the crossing of a moving load over a beam. In this case, the presence of a nonlinearity in the beam behaviour can cause a significant alteration of the modal parameters extracted from the linearized model, such that the contributions of the two effects are no more distinguishable.

  5. Beam heat load investigations with a cold vacuum chamber for diagnostics in a synchrotron light source

    Energy Technology Data Exchange (ETDEWEB)

    Voutta, Robert

    2016-04-22

    The beam heat load is a crucial input parameter for the cryogenic design of superconducting insertion devices. To understand the discrepancies between the predicted heat load of an electron beam to a cold bore and the heat load observed in superconducting devices, a cold vacuum chamber for diagnostics has been built. Extensive beam heat load measurements were performed at the Diamond light source. They are analysed systematically and combined with complementary impedance bench measurements.

  6. Beam heat load investigations with a cold vacuum chamber for diagnostics in a synchrotron light source

    OpenAIRE

    Voutta, Robert

    2016-01-01

    The beam heat load is a crucial input parameter for the cryogenic design of superconducting insertion devices. To understand the discrepancies between the predicted heat load of an electron beam to a cold bore and the heat load observed in superconducting devices, a cold vacuum chamber for diagnostics has been built. Extensive beam heat load measurements were performed at the Diamond light source. They are analysed systematically and combined with complementary impedance bench measurements.

  7. Image-based motion compensation for high-resolution extremities cone-beam CT

    Science.gov (United States)

    Sisniega, A.; Stayman, J. W.; Cao, Q.; Yorkston, J.; Siewerdsen, J. H.; Zbijewski, W.

    2016-03-01

    Purpose: Cone-beam CT (CBCT) of the extremities provides high spatial resolution, but its quantitative accuracy may be challenged by involuntary sub-mm patient motion that cannot be eliminated with simple means of external immobilization. We investigate a two-step iterative motion compensation based on a multi-component metric of image sharpness. Methods: Motion is considered with respect to locally rigid motion within a particular region of interest, and the method supports application to multiple locally rigid regions. Motion is estimated by maximizing a cost function with three components: a gradient metric encouraging image sharpness, an entropy term that favors high contrast and penalizes streaks, and a penalty term encouraging smooth motion. Motion compensation involved initial coarse estimation of gross motion followed by estimation of fine-scale displacements using high resolution reconstructions. The method was evaluated in simulations with synthetic motion (1-4 mm) applied to a wrist volume obtained on a CMOS-based CBCT testbench. Structural similarity index (SSIM) quantified the agreement between motion-compensated and static data. The algorithm was also tested on a motion contaminated patient scan from dedicated extremities CBCT. Results: Excellent correction was achieved for the investigated range of displacements, indicated by good visual agreement with the static data. 10-15% improvement in SSIM was attained for 2-4 mm motions. The compensation was robust against increasing motion (4% decrease in SSIM across the investigated range, compared to 14% with no compensation). Consistent performance was achieved across a range of noise levels. Significant mitigation of artifacts was shown in patient data. Conclusion: The results indicate feasibility of image-based motion correction in extremities CBCT without the need for a priori motion models, external trackers, or fiducials.

  8. New diagnostic technique for Zeeman-compensated atomic beam slowing: technique and results

    OpenAIRE

    Molenaar, P.A.; Van Der Straten, P.; Heideman, H.G.M.; Metcalf, H

    2001-01-01

    We have developed a new diagnostic tool for the study of Zeeman-compensated slowing of an alkali atomic beam. Our time-of-flight technique measures the longitudinal veloc- ity distribution of the slowed atoms with a resolution below the Doppler limit of 30 cm/s. Furthermore, it can map the position and velocity distribution of atoms in either ground hyperfine level inside the solenoid without any devices inside the solenoid. The technique reveals the optical pumping ef- fects, and shows in de...

  9. Tunable chirped fiber Bragg grating embedded in a textile laminated beam for fiber dispersion compensation

    Science.gov (United States)

    Du, Weichong; Liu, W. P.; Du, David G.; Tam, Hwa-Yaw; Tao, Xiaoming; Yu, ChongXiu; Liu, Shong Hao

    1998-06-01

    A simple method is reported for transformation of a uniform fiber grating into a linear chirped grating and realization of independent tuning of grating's linear chirp degree and central wavelength. This method involves embedding a uniform grating into a textile laminated beam and creating an odd- symmetrical linear strain distribution along the grating versus its center with a three-point-bending and stretching setup. The grating's central wavelength and chirp degree can be tuned by adjusting the horizontal stretching range and vertical bending displacement on the beam independently. A simulated experiment for compensating the dispersion of a standard single-mode fiber over 100km for 10Gbit/s signal at 1550nm window is successfully demonstrated using such a tunable chirped grating with 10 cm in length.

  10. Influence of Transient Beam Loading on the Longitudinal Beam Dynamics at BESSY VSR

    OpenAIRE

    Ruprecht, M.; Goslawski, P.; Jankowiak, A.; Neumann, A.; Ries, M; Wüstefeld, G.; Weis, T.

    2015-01-01

    BESSY VSR, a scheme where 1.7 ps and 15 ps long bunches rms can be stored simultaneously in the BESSY II storage ring has recently been proposed [1]. The strong longitudinal bunch focusing is achieved by superconducting high gradient RF cavities. If the bunch fill pattern exhibits a significant inhomogeneity, e.g. due to gaps, transient beam loading causes a distortion of the longitudinal phase space which is different for each bunch. The result are variations along the fill pattern...

  11. Dynamic Responses of Supported Beams with Intermediate Supports Under Moving Loads

    Directory of Open Access Journals (Sweden)

    Biaobiao Zhang

    2012-01-01

    Full Text Available In this paper, a new beam shape function configuration method for determining transient responses of a finite Euler-Bernoulli beam with two intermediate supports excited by moving pressure wave loads is developed. To clarify this method, this beam structure is excited by the moving sinusoidal loads as an example. Transient responses of this beam structure are investigated and verified by the traditional finite element method. This method can be used to solve transient response problems of moving pressure loads exciting the beam structure with intermediate support. Actually it can be extended to solve other complicated beam structure problems.

  12. Springback Prediction and Compensation for a High Strength Steel Side Impact Beam

    Science.gov (United States)

    Dutton, Trevor; Edwards, Richard; Blowey, Andrew

    2005-08-01

    Prediction of formability for sheet metal pressings has advanced to a high state of confidence in recent years. The major challenge is now to predict springback and, moreover, to assist in the design of tooling to correctly compensate for springback. This is particularly the case for materials now being routinely considered for automotive production, such as aluminium and ultra high strength steels, which are prone to greater degrees of springback than traditional mild steels. This paper presents a case study based on the tool design for an ultra high strength steel side impact beam. The forming and springback simulations, carried out using eta/DYNAFORM (based on the LS-DYNA solver), are reported and compared to measurements from the prototype panels. The analysis parameters used in the simulation are presented, and the sensitivity of the results to variation in physical properties is also reviewed. The process of compensating the tools based on the analysis prediction is described; finally, an automated springback compensation method is also applied and the results compared with the final tool design.

  13. Beam pattern improvement by compensating array nonuniformities in a guided wave phased array

    Science.gov (United States)

    Kwon, Hyu-Sang; Lee, Seung-Seok; Kim, Jin-Yeon

    2013-08-01

    This paper presents a simple data processing algorithm which can improve the performance of a uniform circular array based on guided wave transducers. The algorithm, being intended to be used with the delay-and-sum beamformer, effectively eliminates the effects of nonuniformities that can significantly degrade the beam pattern. Nonuniformities can arise intrinsically from the array geometry when the circular array is transformed to a linear array for beam steering and extrinsically from unequal conditions of transducers such as element-to-element variations of sensitivity and directivity. The effects of nonuniformities are compensated by appropriately imposing weight factors on the elements in the projected linear array. Different cases are simulated, where the improvements of the beam pattern, especially the level of the highest sidelobe, are clearly seen, and related issues are discussed. An experiment is performed which uses A0 mode Lamb waves in a steel plate, to demonstrate the usefulness of the proposed method. The discrepancy between theoretical and experimental beam patterns is explained by accounting for near-field effects.

  14. Investigation of ion beam space charge compensation with a 4-grid analyzer

    Science.gov (United States)

    Ullmann, C.; Adonin, A.; Berezov, R.; Chauvin, N.; Delferrière, O.; Fils, J.; Hollinger, R.; Kester, O.; Senée, F.; Tuske, O.

    2016-02-01

    Experiments to investigate the space charge compensation of pulsed high-current heavy ion beams are performed at the GSI ion source text benches with a 4-grid analyzer provided by CEA/Saclay. The technical design of the 4-grid analyzer is revised to verify its functionality for measurements at pulsed high-current heavy ion beams. The experimental investigation of space charge compensation processes is needed to increase the performance and quality of current and future accelerator facilities. Measurements are performed directly downstream a triode extraction system mounted to a multi-cusp ion source at a high-current test bench as well as downstream the post-acceleration system of the high-current test injector (HOSTI) with ion energies up to 120 keV/u for helium and argon. At HOSTI, a cold or hot reflex discharge ion source is used to change the conditions for the measurements. The measurements were performed with helium, argon, and xenon and are presented. Results from measurements with single aperture extraction systems are shown.

  15. Investigation of ion beam space charge compensation with a 4-grid analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Ullmann, C., E-mail: c.ullmann@gsi.de; Adonin, A.; Berezov, R.; Fils, J.; Hollinger, R.; Kester, O. [GSI, Darmstadt (Germany); Chauvin, N.; Delferrière, O.; Senée, F.; Tuske, O. [CEA, Saclay (France)

    2016-02-15

    Experiments to investigate the space charge compensation of pulsed high-current heavy ion beams are performed at the GSI ion source text benches with a 4-grid analyzer provided by CEA/Saclay. The technical design of the 4-grid analyzer is revised to verify its functionality for measurements at pulsed high-current heavy ion beams. The experimental investigation of space charge compensation processes is needed to increase the performance and quality of current and future accelerator facilities. Measurements are performed directly downstream a triode extraction system mounted to a multi-cusp ion source at a high-current test bench as well as downstream the post-acceleration system of the high-current test injector (HOSTI) with ion energies up to 120 keV/u for helium and argon. At HOSTI, a cold or hot reflex discharge ion source is used to change the conditions for the measurements. The measurements were performed with helium, argon, and xenon and are presented. Results from measurements with single aperture extraction systems are shown.

  16. Simulation Study on the Emittance Compensation of Off-axis Emitted Beam in RF Photoinjector

    CERN Document Server

    Huang, Rui-Xuan; Jia, Qi-Ka; Papadopoulos, Christos; Sannibale, Fernando

    2016-01-01

    To make full use of photocathode material and improve its quantum efficiency lifetime, it can be necessary to operate laser away from the cathode center in photoinjectors. In RF guns, the off-axis emitted beam will see a time-dependent RF effect, which would generate a significant growth in transverse emittance. It has been demonstrated that such an emittance growth can be almost completely compensated by orienting the beam on a proper orbit in the downstream RF cavities along the injector. In this paper we analyze in detail the simulation techniques used in reference[1] and the issues associated with them. The optimization of photoinjector systems involving off-axis beams is a challenging problem. To solve this problem, one needs advanced simulation tools including both genetic algorithms and an efficient algorithm for 3D space charge. In this paper, we report on simulation studies where the two codes ASTRA and IMPACT-T are used jointly to overcome these challenges, in order to optimize a system designed to ...

  17. Experimental Study of RC Beams Strengthened with CFRP Sheets Under Sustaining Loads

    Institute of Scientific and Technical Information of China (English)

    WANG Wenwei; LI Guo

    2006-01-01

    Seven reinforced concrete (RC) beams strengthened in flexure using carbon fiber reinforced polymer (CFRP) sheets subjected to different sustaining loads were tested. The effects of initial load and load history on the ultimate strength of strengthened RC beams were examined by externally bonded CFRP sheets. The main experimental parameters included different levels of sustaining load at the time of strengthening, and load history. Experimental results show that sustaining load levels at the time of strengthening have important influences on the ultimate strength of strengthened RC beams. If the initial load is the same, the ultimate strength of RC beams strengthened with CFRP sheets is almost the same regardless of load history at the time of strengthening.

  18. Force control compensation method with variable load stiffness and damping of the hydraulic drive unit force control system

    Science.gov (United States)

    Kong, Xiangdong; Ba, Kaixian; Yu, Bin; Cao, Yuan; Zhu, Qixin; Zhao, Hualong

    2016-05-01

    Each joint of hydraulic drive quadruped robot is driven by the hydraulic drive unit (HDU), and the contacting between the robot foot end and the ground is complex and variable, which increases the difficulty of force control inevitably. In the recent years, although many scholars researched some control methods such as disturbance rejection control, parameter self-adaptive control, impedance control and so on, to improve the force control performance of HDU, the robustness of the force control still needs improving. Therefore, how to simulate the complex and variable load characteristics of the environment structure and how to ensure HDU having excellent force control performance with the complex and variable load characteristics are key issues to be solved in this paper. The force control system mathematic model of HDU is established by the mechanism modeling method, and the theoretical models of a novel force control compensation method and a load characteristics simulation method under different environment structures are derived, considering the dynamic characteristics of the load stiffness and the load damping under different environment structures. Then, simulation effects of the variable load stiffness and load damping under the step and sinusoidal load force are analyzed experimentally on the HDU force control performance test platform, which provides the foundation for the force control compensation experiment research. In addition, the optimized PID control parameters are designed to make the HDU have better force control performance with suitable load stiffness and load damping, under which the force control compensation method is introduced, and the robustness of the force control system with several constant load characteristics and the variable load characteristics respectively are comparatively analyzed by experiment. The research results indicate that if the load characteristics are known, the force control compensation method presented in this

  19. Space-charge compensation measurements in electron cyclotron resonance ion source low energy beam transport lines with a retarding field analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Winklehner, D.; Leitner, D., E-mail: leitnerd@nscl.msu.edu; Cole, D.; Machicoane, G.; Tobos, L. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)

    2014-02-15

    In this paper we describe the first systematic measurement of beam neutralization (space charge compensation) in the ECR low energy transport line with a retarding field analyzer, which can be used to measure the potential of the beam. Expected trends for the space charge compensation levels such as increase with residual gas pressure, beam current, and beam density could be observed. However, the overall levels of neutralization are consistently low (<60%). The results and the processes involved for neutralizing ion beams are discussed for conditions typical for ECR injector beam lines. The results are compared to a simple theoretical beam plasma model as well as simulations.

  20. Beam loading by distributed injection of electrons in a plasma wakefield accelerator.

    Science.gov (United States)

    Vafaei-Najafabadi, N; Marsh, K A; Clayton, C E; An, W; Mori, W B; Joshi, C; Lu, W; Adli, E; Corde, S; Litos, M; Li, S; Gessner, S; Frederico, J; Fisher, A S; Wu, Z; Walz, D; England, R J; Delahaye, J P; Clarke, C I; Hogan, M J; Muggli, P

    2014-01-17

    We show through experiments and supporting simulations that propagation of a highly relativistic and dense electron bunch through a plasma can lead to distributed injection of electrons, which depletes the accelerating field, i.e., beam loads the wake. The source of the injected electrons is ionization of the second electron of rubidium (Rb II) within the wake. This injection of excess charge is large enough to severely beam load the wake, and thereby reduce the transformer ratio T. The reduction of the average T with increasing beam loading is quantified for the first time by measuring the ratio of peak energy gain and loss of electrons while changing the beam emittance. Simulations show that beam loading by Rb II electrons contributes to the reduction of the peak accelerating field from its weakly loaded value of 43  GV/m to a strongly loaded value of 26  GV/m.

  1. Effects of axial load and structural damping on wave propagation in periodic Timoshenko beams on elastic foundations under moving loads

    Science.gov (United States)

    Ding, Lan; Zhu, Hong-Ping; Wu, Li

    2016-07-01

    The propagation and attenuation properties of waves in ordered and disordered periodic composite Timoshenko beams, which consider the effects of axial static load and structural damping, resting on elastic foundations are studied when the system is subjected to moving loads of constant amplitude with a constant velocity. The transfer matrix methodology is adopted to formulate the model in a reference coordinate system moving with the load. The localization factor is calculated to determine the wave velocity pass bands and stop bands. The interactions between the static axial load and moving load, structural damping and disorder on the bands are analyzed.

  2. Compensation of errors due to incident beam drift in a 3 DOF measurement system for linear guide motion.

    Science.gov (United States)

    Hu, Pengcheng; Mao, Shuai; Tan, Jiu-Bin

    2015-11-01

    A measurement system with three degrees of freedom (3 DOF) that compensates for errors caused by incident beam drift is proposed. The system's measurement model (i.e. its mathematical foundation) is analyzed, and a measurement module (i.e. the designed orientation measurement unit) is developed and adopted to measure simultaneously straightness errors and the incident beam direction; thus, the errors due to incident beam drift can be compensated. The experimental results show that the proposed system has a deviation of 1 μm in the range of 200 mm for distance measurements, and a deviation of 1.3 μm in the range of 2 mm for straightness error measurements.

  3. Shear Behavior of Novel Prestressed Concrete Beam Subjected to Monotonic and Cyclic Loading

    Institute of Scientific and Technical Information of China (English)

    余芳; 姚大立; 贾金青; 吴锋

    2014-01-01

    Prestressed steel ultrahigh-strength reinforced concrete (PSURC) beam is a new type of prestressed con-crete beam, which not only has a considerable compressive strength attributed to the ultrahigh strength concrete, but also ensures a certain degree of ductility at failure due to the existence of structural steel. Five of these beams were monotonically tested until shear failure to investigate the static shear performance including the failure pattern, load-deflection behavior, shear capacity, shear crack width and shear ductility. The experimental results show that these beams have superior shear capacity, crack control ability and shear ductility. To study the shear performance under repeated overloading, seven PSURC beams were loaded in cyclic test simultaneously. The overall shear performance of cycled beams is similar to that of uncycled beams at low load level but different at high load level. The shear capac-ity and crack control ability of cycled beams at high load level are reduced, whereas the shear ductility is improved. In addition, the influences of variables including the degree of prestress, stirrup ratio and load level on the shear perform-ance of both uncycled and cycled beams were also discussed and compared, respectively.

  4. Inverse problem of elastica of a variable-arc-length beam subjected to a concentrated load

    Institute of Scientific and Technical Information of China (English)

    Xiaowei Zhang; Jialing Yang; Keren Wang

    2005-01-01

    An inverse problem of elastica of a variable-arclength beam subjected to a concentrated load is investigated.The beam is fixed at one end, and can slide freely over a hinge support at the other end. The inverse problem is to determine the value of the load when the deflection of the action point of the load is given. Based on the elasitca equations and the elliptic integrals, a set of nonlinear equations for the inverse problem are derived, and an analytical solution by means of iterations and Quasi-Newton method is presented. From the results, the relationship between the loads and deflections of the loading point is obtained.

  5. Microwave measurements and beam dynamics simulations of the BNL/SLAC/UCLA emittance-compensated 1.6-cell photocathode rf gun

    Science.gov (United States)

    Palmer, Dennis T.; Miller, Roger H.; Winick, Herman; Wang, Xi J.; Batchelor, Kenneth; Woodle, Martin H.; Ben-Zvi, Ilan

    1995-09-01

    A dedicated low energy (2 to 10 MeV) experimental beam line is now under construction at Brookhaven National Laboratory/Accelerator Test Facility (BNL/ATF) for photocathode RF gun testing and photoemission experiments. Microwave measurements of the 1.6 cell photocathode RF gun have been conducted along with beam dynamics simulations of the emittance compensated low energy beam. These simulations indicate that the 1.6 cell photocathode RF gun in combination with solenoidal emittance compensation will be capable of producing a high brightness beam with a normalization rms emittance of (epsilon) n,rms approximately equals 1 (pi) mm mrad. The longitudinal accelerating field Ez has been measured as a function of azimuthal angle in the full cell of the cold test model for the 1.6 cell BNL/SLAC/UCLA #3 S-band RF Gun using a needle rotation/frequency perturbation technique. These measurements were conducted before and after symmetrizing the full cell with a vacuum pump out port and an adjustable short. Two different waveguide to full cell coupling schemes were studied. Experimental and theoretical studies of the field balance versus mode separation were conducted. The dipole mode of the full cell using the (theta) - coupling scheme is an order of magnitude less severe before symmetrization than the Z- coupling scheme. The multi-pole contribution to the longitudinal field asymmetry are calculated using standard Fourier series techniques for both coupling schemes. The Panofsky- Wenzel theorem is used in estimating the transverse emittance due to the multipole components of Ez. Detailed beam dynamics simulations were performed for the 1.6 cell photocathode RF gun injector using a solenoidal emittance compensation technique. The design of the experimental line along with a proposed experimental program using the 1.6 cell photocathode RF gun developed by the BNL/SLAC/UCLA RF gun collaboration is presented. This experimental program includes measurements of beam loading caused

  6. Load history-based model for prestressed concrete beam damage evaluation

    Institute of Scientific and Technical Information of China (English)

    Yuan Jianli; Wang Yi; Qian Zhonghui

    2007-01-01

    The residual capability of a damaged structure to resist further load is essential in optimal seismic design and post-earthquake strengthening.An experimental study on the hysteretic characteristics of prestressed concrete frame beams under different loading histories was performed to explore the influence of load history on energy dissipation and failure characteristics of the member.Based on the test results,the failure of the beam is defined,and the relationship between the failure moment under cyclic load and from the skeleton curve is formulated.Finally,based on displacement and energy dissipation,a model for prestressed concrete beam damage-failure evaluation is developed.In this model,the effect of deformation level,cumulative dissipated energy,and loading history on prestressed concrete beam damage-failure is incorporated,thus it is applicable to stochastic earthquake forces.

  7. RC beam strengthened with pre-stressed CFP under the secondary load

    Institute of Scientific and Technical Information of China (English)

    LONG Bang-yun; YUAN Guang-lin; ZHU Dan-yu

    2008-01-01

    Feasibility of using pre-stressed carbon fiber plates to strengthen reinforced concrete beams was studied. Based on the characteristics of carbon fiber plates, we developed a pre-stress clamp and a device for applying the pre-stress. Contrast tests were conducted between ordinary carbon fiber plates and a pre-stressed carbon fiber plate and between secondary loaded carbon fiber plates and a concrete beam strengthened with a secondary loaded carbon fiber plate. On this basis, we analyzed the failure pattern,the width of cracks and their distribution, the cracking load, the yield load, the limit load and the relation between load and deflection. The results indicate that using pre-stressed carbon fiber plates to strengthen concrete beams is feasible and effective.

  8. Study of the transient effects of the space charge compensation on the dynamics of an intense beam; Etude des effets transitoires de la compensation de charge d'espace sur la dynamique d'un faisceau intense

    Energy Technology Data Exchange (ETDEWEB)

    Ben Ismail, A

    2005-09-15

    A main interest in the design of ion accelerators is the control of the dynamics of intense beams at low energy. This dynamics is dominated by nonlinear effects of the Space Charge (SC) field. This SC field induces a halo formation which can induce losses along the transport. Once ionized by the beam, the residual gas, diffused by the source and produced by the desorption of the vacuum chamber of the accelerator, contributes to the production of electrons and ions. According to their sign of charge compared to the beam, these particles will be repelled or confined. The accumulation of particles in the beam contributes to the compensation of the SC field. However, this neutralization induces other non linearity which are dependent on time. This thesis presents an experimental and theoretical work of the SC compensation for ion beams (H{sup +} and H{sup -}). The dynamics of these beams is modelled by a new PIC code, CARTAGO, ensuring the coupling between the created plasma and the studied beams. A single-particle study introduces the dynamics of the plasma in presence of the SC field and of an external magnetic field. The modeling of the compensation with the 1D version of CARTAGO code gave the establishment times and the compensation degrees for several cases of beams and various gas pressures. The compensation of a protons beam was studied more particularly in the low-energy line of the Injector of Protons of High Intensity (IPHI) at Saclay. Simulations show an over-compensation of the space charge inside the focusing solenoid and outside the compensation is only partial. Experimental confrontations of the 2D(r,z) modeling results in a part of this line are also detailed. (author)

  9. Evaluation of plastic materials for range shifting, range compensation, and solid-phantom dosimetry for carbon-ion beams

    CERN Document Server

    Kanematsu, Nobuyuki; Ogata, Risa

    2012-01-01

    Purpose: Beam range control is the essence of radiotherapy with heavy charged particles. In conventional broad-beam delivery, fine range adjustment is achieved by insertion of range shifting and compensating materials. Ideally, such material should be water equivalent as well as that for dosimetry. In this study, we evaluated dosimetric water equivalency of four common plastics, HDPE, PMMA, PET, and POM, by uniformity of effective densities for carbon-ion-beam interactions. Methods: Using the Bethe formula for stopping, the Gottschalk formula for multiple scattering, and the Sihver formula for nuclear interactions, we calculated the effective densities of the plastics for these interactions. We tested HDPE, PMMA, and POM in carbon-ion-beam experiment and measured attenuations of carbon ions, which were compared with empirical linear-attenuation-model calculations. Results: The theoretical calculations resulted in reduced multiple scattering and increased nuclear interactions for HDPE compared to water, which ...

  10. Calculation of force distribution for a periodically supported beam subjected to moving loads

    Science.gov (United States)

    Hoang, T.; Duhamel, D.; Foret, G.; Yin, H. P.; Joyez, P.; Caby, R.

    2017-02-01

    In this study, a novel model for a periodically supported beam subjected to moving loads was developed using a periodicity condition on reaction forces. This condition, together with Fourier transforms and Dirac combs, forms a relation between the beam displacement and support reaction forces. This relation explains the force distribution at the supports, and holds for any type of support and foundation behaviors. Based on this relation, a system equivalence for a periodically supported beam is presented in this paper. An application to non-ballasted viscoelastic supports is presented as an example and the results clearly match the existing model. Next, an approximation of real-time responses was developed for the moving loads as periodic series. The comparison shows that this approximation can be used for a limited number of loads if the distances between loads are sufficiently large. The system equivalence for a periodically supported beam is efficient for supports with linear behavior, and could be extended to other behaviors.

  11. The stability of beam with two billeting arbitrarily, but symmetrical support under action of follow loading

    Directory of Open Access Journals (Sweden)

    V.Ts. Gnuni

    2016-03-01

    Full Text Available The non-conservative stability problem of pressing beam when two support billeting symmetrical on arbitrarily distance from the end is considered. It is show the possibility statical form loss of stability. The critical loads are determined.

  12. Determining critical load in the multispan beams with the nonlinear model

    Science.gov (United States)

    DemÑ-r, D. Dönmez; Sinir, B. G.; Usta, L.

    2017-01-01

    The beams which are one of the most commonly used structural members are quite important for many researchers. Mathematical models determining the response of beams under external loads are concluded from elasticity theory through a series of assumptions concerning the kinematics of deformation and constitutive behavior. In this study, the derivation of the nonlinear model is introduced to determine the critical load in the multispan beams. Since the engineering practice of this kind of problems is very common, determining the critical load is quite important. For this purpose, the nonlinear mathematical model of the multispan Euler-Bernoulli beam is firstly obtained. To be able to obtain the independent of the material and the geometry, the present model are became dimensionless. Then, the critical axial load can be determined via the nonlinear solution of the governing equation.

  13. Temperature calculations of heat loads in rotating target wheels exposed to high beam currents.

    Energy Technology Data Exchange (ETDEWEB)

    Greene, J. P.; Gabor, R.; Neubauer, J.

    2000-11-29

    In heavy-ion physics, high beam currents can eventually melt or destroy the target. Tightly focused beams on stationary targets of modest melting point will exhibit short lifetimes. Defocused or wobbled beams are employed to enhance target survival. Rotating targets using large diameter wheels can help overcome target melting and allow for higher beam currents to be used in experiments. The purpose of the calculations in this work is to try and predict the safe maximum beam currents which produce heat loads below the melting point of the target material.

  14. Potential load reductions on megawatt turbines exposed to wakes using individual-pitch wake compensator and trailing-edge flaps

    DEFF Research Database (Denmark)

    Markou, Helen; Andersen, Peter Bjørn; Larsen, Gunner Chr.

    2011-01-01

    that typically focus on either load or power prediction. As a consequence, the wake affected inflow field generated by the DWM formulation opens for control strategies for the individual turbine. Two different control approaches for load reduction on the individual turbines are implemented in the multi-body aero......, is extracted from measurements of the blade-root bending moment and/or one-point recordings of flow angle of attack to the blades (pitot tube) measurements. In the former implementation, the pitch angle of each blade is compensated for as an addition to the collective-pitch, rotor-speed control. In the latter...

  15. Transient response of a beam on viscoelastic foundation under an impact load during nondestructive testing

    Institute of Scientific and Technical Information of China (English)

    Lu Sun; Feiquan Luo; Tung-Huei Chen

    2005-01-01

    Beam responses under an impact NDT load are studied using the Fourier and Laplace transforms. Numerical computation is performed for a parametric study of beam and load parameters. It is shown that under an impact load, the time duration for displacement to vanish is ten times longer than that for velocity and acceleration. The maximum response is achieved first in acceleration, followed by velocity, and finally displacement, all of which occur before the impact load is removed. At the moment that the impact load is removed from the beam, there is a discontinuity in the velocity and acceleration responses, but not in displacement response. The effect of K and ph on beam response is much less significant than that of EI and C, which have similar effect on beam response. As EI increases, peak values of displacement, velocity and acceleration response decrease. The effect of K on beam response only becomes appreciable after the impact load is removed.While the peak of displacement remain almost unchanged as K increases, the displacement response decays to zero faster for large K values than for small K values.

  16. Compensating microphonics in SRF cavities to ensure beam stability for future free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Axel

    2008-07-21

    In seeded High-Gain-Harmonic-Generation free electron lasers or energy recovery linear accelerators the requirements for the bunch-to-bunch timing and energy jitter of the beam are in the femtosecond and per mill regime. This implies the ability to control the cavity radiofrequency (RF) field to an accuracy of 0.02 in phase and up to 1.10{sup -4} in amplitude. For the planned BESSY-FEL it is envisaged to operate 144 superconducting 1.3 GHz cavities of the 2.3 GeV driver linac in continuous wave mode and at a low beam current. The cavity resonance comprises a very narrow bandwidth of the order of tens of Hertz. Such cavities have been characterized under accelerator like conditions in the HoBiCaT test facility. It was possible to measure the error sources affecting the field stability in continuous wave (CW) operation. Microphonics, the main error source for a mechanical detuning of the cavities, lead to an average fluctuation of the cavity resonance of 1-5 Hz rms. Furthermore, the static and dynamic Lorentz force detuning and the helium pressure dependance of the cavity resonance have been measured. Single cavity RF control and linac bunch-to-bunch longitudinal phase space modeling containing the measured properties showed, that it is advisable to find means to minimize the microphonics detuning by mechanical tuning. Thus, several fast tuning systems have been tested for CW operation. These tuners consist of a motor driven lever for slow and coarse tuning and a piezo that is integrated into the tuner support for fast and fine tuning. Regarding the analysis of the detuning spectrum an adaptive feedforward method based on the least-mean-square filter algorithm has been developed for fast cavity tuning. A detuning compensation between a factor of two and up to a factor of seven has been achieved. Modeling the complete system including the fast tuning scheme, showed that the requirements of the BESSY-FEL are attainable. (orig.)

  17. Duration of load behaviour of different sized straight timber beams subjected to bending in variable climate

    DEFF Research Database (Denmark)

    Hanhijärvi, A.; Galimard, P.; Hoffmeyer, Preben

    1998-01-01

    The paper is the second in a series which sums up the results of an extensive project to quantify the duration-of-load (DOL) effect on different sized timber beams in different climates. The paper deals with straight (unnotched) beams. The results of various DOL-tests of stepwise and constant ben...

  18. Five-dimensional motion compensation for respiratory and cardiac motion with cone-beam CT of the thorax region

    Science.gov (United States)

    Sauppe, Sebastian; Hahn, Andreas; Brehm, Marcus; Paysan, Pascal; Seghers, Dieter; Kachelrieß, Marc

    2016-03-01

    We propose an adapted method of our previously published five-dimensional (5D) motion compensation (MoCo) algorithm1, developed for micro-CT imaging of small animals, to provide for the first time motion artifact-free 5D cone-beam CT (CBCT) images from a conventional flat detector-based CBCT scan of clinical patients. Image quality of retrospectively respiratory- and cardiac-gated volumes from flat detector CBCT scans is deteriorated by severe sparse projection artifacts. These artifacts further complicate motion estimation, as it is required for MoCo image reconstruction. For high quality 5D CBCT images at the same x-ray dose and the same number of projections as todays 3D CBCT we developed a double MoCo approach based on motion vector fields (MVFs) for respiratory and cardiac motion. In a first step our already published four-dimensional (4D) artifact-specific cyclic motion-compensation (acMoCo) approach is applied to compensate for the respiratory patient motion. With this information a cyclic phase-gated deformable heart registration algorithm is applied to the respiratory motion-compensated 4D CBCT data, thus resulting in cardiac MVFs. We apply these MVFs on double-gated images and thereby respiratory and cardiac motion-compensated 5D CBCT images are obtained. Our 5D MoCo approach processing patient data acquired with the TrueBeam 4D CBCT system (Varian Medical Systems). Our double MoCo approach turned out to be very efficient and removed nearly all streak artifacts due to making use of 100% of the projection data for each reconstructed frame. The 5D MoCo patient data show fine details and no motion blurring, even in regions close to the heart where motion is fastest.

  19. A Technique for Temperature and Ultimate Load Calculations of Thin Targets in a Pulsed Electron Beam

    DEFF Research Database (Denmark)

    Hansen, Jørgen-Walther; Lundsager, Per

    1979-01-01

    A technique is presented for the calculation of transient temperature distributions and ultimate load of rotationally symmetric thin membranes with uniform lateral load and exposed to a pulsed electron beam from a linear accelerator. Heat transfer by conduction is considered the only transfer...

  20. STEADY-STATE RESPONSE OF A TIMOSHENKO BEAM ON AN ELASTIC HALF-SPACE UNDER A MOVING LOAD

    Institute of Scientific and Technical Information of China (English)

    Chen Yunmin; Wang Changjing

    2006-01-01

    By introducing the equivalent stiffness of an elastic half-space interacting with a Timoshenko beam, the displacement solution of the beam resting on an elastic half-space subjected to a moving load is presented. Based on the relative relation of wave velocities of the half-space and the beam, four cases with the combination of different parameters of the half-space and the beam, the system of soft beam and hard half-space, the system of sub-soft beam and hard halfspace, the system of sub-hard beam and soft half-space, and the system of hard beam and soft half-space are considered. The critical velocities of the moving load are studied using dispersion curves. It is found that critical velocities of the moving load on the Timoshenko beam depend on the relative relation of wave velocities of the half-space and the beam. The Rayleigh wave velocity in the half-space is always a critical velocity and the response of the system will be infinite when the load velocity reaches it. For the system of soft beam and hard half-space, wave velocities of the beam are also critical velocities. Besides the shear wave velocity of the beam, there is an additional minimum critical velocity for the system of sub-soft beam and hard half-space. While for systems of (sub-) hard beams and soft half-space, wave velocities of the beam are no longer critical ones.Comparison with the Euler-Bernoulli beam shows that the critical velocities and response of the two types of beams are much different for the system of (sub-) soft beam and hard half-space but are similar to each other for the system of (sub-) hard beam and soft half space. The largest displacement of the beam is almost at the location of the load and the displacement along the beam is almost symmetrical if the load velocity is smaller than the minimum critical velocity (the shear wave velocity of the beam for the system of soft beam and hard half-space). The largest displacement of the beam shifts behind the load and the asymmetry

  1. Experimental Studies on Behaviour of Reinforced Geopolymer Concrete Beams Subjected to Monotonic Static Loading

    Science.gov (United States)

    Madheswaran, C. K.; Ambily, P. S.; Dattatreya, J. K.; Ramesh, G.

    2015-06-01

    This work describes the experimental investigation on behaviour of reinforced GPC beams subjected to monotonic static loading. The overall dimensions of the GPC beams are 250 mm × 300 mm × 2200 mm. The effective span of beam is 1600 mm. The beams have been designed to be critical in shear as per IS:456 provisions. The specimens were produced from a mix incorporating fly ash and ground granulated blast furnace slag, which was designed for a compressive strength of 40 MPa at 28 days. The reinforced concrete specimens are subjected to curing at ambient temperature under wet burlap. The parameters being investigated include shear span to depth ratio (a/d = 1.5 and 2.0). Experiments are conducted on 12 GPC beams and four OPCC control beams. All the beams are tested using 2000 kN servo-controlled hydraulic actuator. This paper presents the results of experimental studies.

  2. Load carrying capacity of RCC beams by replacing steel reinforcement bars with shape memory alloy bars

    Science.gov (United States)

    Bajoria, Kamal M.; Kaduskar, Shreya S.

    2016-04-01

    In this paper the structural behavior of reinforced concrete (RC) beams with smart rebars under two point loading system has been numerically studied, using Finite Element Method. The material used in this study is Super-elastic Shape Memory Alloys (SE SMAs) which contains nickel and titanium. In this study, different quantities of steel and SMA rebars have been used for reinforcement and the behavior of these models under two point bending loading system is studied. A comparison of load carrying capacity for the model between steel reinforced concrete beam and the beam reinforced with S.M.A and steel are performed. The results show that RC beams reinforced with combination of shape memory alloy and steel show better performance.

  3. Beam Halo on the LHC TCDQ Diluter System and Thermal Load on the Downstream Superconducting Magnets

    CERN Document Server

    Goddard, B; Presland, A; Redaelli, S; Robert-Démolaize, G; Sarchiapone, L; Weiler, T; Weterings, W

    2006-01-01

    The moveable single-jawed graphite TCDQ diluter must be positioned very close to the circulating LHC beam in order to prevent damage to downstream components in the event of an unsynchronised beam abort. A two-jawed graphite TCS.IR6 collimator forms part of the TCDQ system. The requirement to place the jaws close to the beam means that the system can intercept a substantial beam halo load. Initial investigations indicated a worryingly high heat load on the Q4 coils. This paper presents the updated load cases, shielding and simulation geometry, and the results of simulations of the energy deposition in the TCDQ system and in the downstream superconducting Q4 magnet. The implications for the operation of the LHC are discussed.

  4. Evaluation of Coordinate Compensator Structure Based on Power Injection Model for Loading Margin Enhancement in Power Systems

    Directory of Open Access Journals (Sweden)

    Reza Sedaghati

    2013-09-01

    Full Text Available In this paper, the structure of Hybrid Power Flow Controller (HPFC is proposed in order to improve static voltage stability characteristics. HPFC forms a hybrid controller using IPFC series converters as a hybrid with existing parallel and passive compensator (SVC in power system. Utilization of hybrid structures makes it possible to use converters for improving performance of both old and existing compensators in power networks. In this study, the power injection model (PIM is used to model the hybrid power flow controller in Newton load flow. The aforementioned model is simulated in MATLAB software. The P-V curves of PQ buses of a typical system are evaluated by a continuous power flow (CPF method to analyses the effect of this controller on static voltage stability characteristics. Meanwhile, SVC as existing devices in the system and UPFC and IPFC as state-of-the-art compensator devices are compared with the proposed hybrid structure. The amount of active and reactive power loss and improvement of loading limit of the system are used as main parameters in our comparison.

  5. THE STRENGTH OF REINFORCED CONCRETE BEAM ELEMENTS UNDER CYCLIC ALTERNATING LOADING AND LOW CYCLE LOAD OF CONSTANT SIGN

    Directory of Open Access Journals (Sweden)

    Semina Yuliya Anatol'evna

    2015-09-01

    Full Text Available The behavior of reinforced concrete elements under some types of cyclic loads is described in the paper. The main aim of the investigations is research of the stress-strain state and strength of the inclined sections of reinforced concrete beam elements in conditions of systemic impact of constructive factors and the factor of external influence. To spotlight the problem of cyclic loadings three series of tests were conducted by the author. Firstly, the analysis of the tests showed that especially cyclic alternating loading reduces the bearing capacity of reinforced concrete beams and their crack resistance by 20 % due to the fatigue of concrete and reinforcement. Thus the change of load sign creates serious changes of stress-strain state of reinforced concrete beam elements. Low cycle loads of constant sign effect the behavior of the constructions not so adversely. Secondly, based on the experimental data mathematical models of elements’ strength were obtained. These models allow evaluating the impact of each factor on the output parameter not only separately, but also in interaction with each other. Furthermore, the material spotlighted by the author describes stress-strain state of the investigated elements, cracking mechanism, changes of deflection values, the influence of mode cyclic loading during the tests. Since the data on the subject are useful and important to building practice, the ultimate aim of the tests will be working out for improvement of nonlinear calculation models of span reinforced concrete constructions taking into account the impact of these loads, and also there will be the development of engineering calculation techniques of their strength, crack resistance and deformability.

  6. An atomic beam source for fast loading of a magneto-optical trap under high vacuum

    DEFF Research Database (Denmark)

    McDowall, P.D.; Hilliard, Andrew; Grünzweig, T.;

    2012-01-01

    We report on a directional atomic beam created using an alkali metal dispenser and a nozzle. By applying a high current (15 A) pulse to the dispenser at room temperature we can rapidly heat it to a temperature at which it starts dispensing, avoiding the need for preheating. The atomic beam produced...... is capable of loading 90 of a magneto-optical trap (MOT) in less than 7 s while maintaining a low vacuum pressure of 10 -11 Torr. The transverse velocity components of the atomic beam are measured to be within typical capture velocities of a rubidium MOT. Finally, we show that the atomic beam can be turned...

  7. On the dynamic stability of shear deformable beams under a tensile load

    Science.gov (United States)

    Caddemi, S.; Caliò, I.; Cannizzaro, F.

    2016-07-01

    Loss of stability of beams in a linear static context due to the action of tensile loads has been disclosed only recently in the scientific literature. However, tensile instability in the dynamic regime has been only marginally covered. Several aspects concerning the role of shear deformation on the tensile dynamic instability on continuous and discontinuous beams are still to be addressed. It may appear as a paradox, but also for the case of the universally studied Timoshenko beam model, despite its old origin, frequency-axial load diagrams in the range of negative values of the load (i.e. tensile load) has never been brought to light. In this paper, for the first time, the influence of a conservative tensile axial loads on the dynamic behaviour of the Timoshenko model, according to the Haringx theory, is assessed. It is shown that, under increasing tensile loads, regions of positive/negative fundamental frequency variations can be distinguished. In addition, the beam undergoes eigen-mode changes, from symmetric to anti-symmetric shapes, until tensile instability of divergence type is reached. As a further original contribution on the subject, taking advantage of a new closed form solution, it is shown that the same peculiarities are recovered for an axially loaded Euler-Bernoulli vibrating beam with multiple elastic sliders. This latter model can be considered as the discrete counterpart of the Timoshenko beam-column in which the internal sliders concentrate the shear deformation that in the Timoshenko model is continuously distributed. Original aspects regarding the evolution of the vibration frequencies and the relevant mode shapes with the tensile load value are highlighted.

  8. The Attenuation of Flexural Waves in Mass Loaded Beams.

    Science.gov (United States)

    1985-05-01

    would also like to thank Professor Kim Vandiver for the loan of his spectral analyzer. I also want to thank Kodali Rao and Greg Chisholm for their...imaginary part of the fourth root of equation (11). This was done by Mr. Kodali Rao*. He devised a computer program that would generate the magnitude of...EXPERIMENT The author’s principal purpose was to devise an experimental method of testing the analytical model. The beam part of the system was simple enough

  9. Upgrade of the beam transport lines and the beam-abort system and development of a tune compensator in KEKB

    Science.gov (United States)

    Iida, Naoko; Kikuchi, Mitsuo; Mimashi, Toshihiro; Nakayama, Hisayoshi; Sakamoto, Yutaka; Satoh, Kotaro; Takasaki, Seiji; Tawada, Masafumi

    2013-03-01

    The KEKB collider achieved a maximum peak luminosity of 2.1×1034 cm-2 s-1 and an integrated luminosity of 1 ab-1 in its ten-year operation. Behind these glorious records there have been uncountable improvements in every subsystem. This paper describes the improvements in the beam transport line, injection kickers, septum magnets, the beam-abort system, and a newly developed pulsed-quadrupole system in detail.

  10. THE CRITICAL LOAD PARAMETER OF A TIMOSHENKO BEAM WITH ONE-STEP CHANGE IN CROSS SECTION

    Directory of Open Access Journals (Sweden)

    Goran Janevski

    2014-12-01

    Full Text Available The paper analyzes the transverse vibration of a Timoshenko beam with one-step change in cross-section when subjected to an axial force. The axial force is equal in both of the beam portions. Three types of beam which occur commonly in engineering application are considered. The frequency equation of the Timoshenko beam with one-step change in cross-section is expressed as the fourth order determinant equated to zero. The critical compressive axial force is expressed as a function of the critical load parameter which is tabulated for four classical boundary conditions. Apart from the results presented in Tables, the paper also provides calculated values of the critical load parameter for other values of system parameters along with the graphic representation of their dependence on the step position parameter.

  11. An exact dynamic stiffness matrix for axially loaded double-beam systems

    Indian Academy of Sciences (India)

    Li Xiaobin; Xu Shuangxi; Wu Weiguo; Li Jun

    2014-06-01

    An exact dynamic stiffness method is presented in this paper to determine the natural frequencies and mode shapes of the axially loaded double-beam systems,which consist of two homogeneous and prismatic beams with a distributed spring in parallel between them.The effects of the axial force, shear deformation and rotary inertia are considered, as shown in the theoretical formulation. The dynamic stiffness influence coefficients are formulated from the governing differential equations of the axially loaded double-beam system in free vibration by using the Laplace transform method. An example is given to demonstrate the effectiveness of this method, in which ten boundary conditions are investigated and the effect of the axial force on the natural frequencies and mode shapes of the double-beam system are further discussed.

  12. Analysis and Load Rating of Pre-flex Composite Beams

    Science.gov (United States)

    2011-09-01

    buildings and bridges in Asia and Europe (Staquet et al. 2004). The Southern Tower (Tour du Midi) in Belgium employs this system. Other common ...specified by its manufac- turers and varies from 19.62 kN (4,410 lb) to 44.1 kN (9,920 lb). Common practice in the design of reinforced concrete assumes... Mallow = maximum moment allowed Ppf = maximum pre-flexion load fs = allowable stress in steel section Sx = section modulus of steel

  13. Eigenvalues of an axially loaded cantilever beam with an eccentric end rigid body

    CERN Document Server

    Lajimi, S Amir Mousavi

    2014-01-01

    An analytical form of the characteristic equation for a vertically mounted cantilever beam with an end rigid body is obtained and solved for the eigenvalues of the structure. The effect of the weight of the structure is taken into consideration by estimating the load as a function of the length of the beam. The mass, rotary inertia and eccentricity of the end rigid body are demonstrated to considerably affect the eigenvalues of the structure.

  14. A cyclic loading model for beam-to-column web connection

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-bo; XIE li-li; SHAO Yong-song

    2008-01-01

    A finite element analysis of the beam-to-column web connection with H-shaped columns was performed using the ANSYS computer program.Based on the finite element analysis and theoretical analysis,a simplified model was developed to describe the cyclic loading behavior of beam-to-columns web connection in steel moment resisting frames,considering both bending and shear deformation modes of the beam flange plate.Several issues appearing to merit further researches were identified in the process of developing this model,such as the effect of beam flange plate on beam-to-column web connection stiffness and strength.A reasonable agreement was achieved between model predictions and finite element data,which verified the feasibihty of the proposed model.

  15. Dynamic Stresses in the LHC TCDS Diluter from 7 TeV Beam Loading

    CERN Document Server

    Goddard, B; Presland, A; Weterings, W

    2006-01-01

    In the event of an unsynchronised beam abort, the MSD extraction septum of the LHC beam dumping system is protected from damage by the TCDS diluter. The simultaneous constraints of obtaining sufficient beam dilution while ensuring the survival of the TCDS make the design difficult, with high thermally induced dynamic stresses occurring in the material needed to attenuate the particle showers induced by the primary beam impact. In this paper, full 3D simulations are described where the worst-case beam loading has been used to generate the local temperature rise and to follow the resulting time evolution of the mechanical stresses. The results and the accompanying design changes for the TCDS, to provide an adequate performance margin, are detailed.

  16. Beam heat load due to geometrical and resistive wall impedance in COLDDIAG

    Science.gov (United States)

    Casalbuoni, S.; Migliorati, M.; Mostacci, A.; Palumbo, L.; Spataro, B.

    2012-11-01

    One of the still open issues for the development of superconductive insertion devices is the understanding of the heat intake from the electron beam. With the aim of measuring the beam heat load to a cold bore and the hope to gain a deeper understanding in the underlying mechanisms, a cold vacuum chamber for diagnostics (COLDDIAG) was built. It is equipped with the following instrumentation: retarding field analyzers to measure the electron flux, temperature sensors to measure the beam heat load, pressure gauges, and mass spectrometers to measure the gas content. Possible beam heat load sources are: synchrotron radiation, wakefield effects due to geometrical and resistive wall impedance and electron/ion bombardment. The flexibility of the engineering design will allow the installation of the cryostat in different synchrotron light sources. COLDDIAG was first installed in the Diamond Light Source (DLS) in 2011. Due to a mechanical failure of the thermal transition of the cold liner, the cryostat had to be removed after one week of operation. After having implemented design changes in the thermal liner transition, COLDDIAG has been reinstalled in the DLS at the end of August 2012. In order to understand the beam heat load mechanism it is important to compare the measured COLDDIAG parameters with theoretical expectations. In this paper we report on the analytical and numerical computation of the COLDDIAG beam heat load due to coupling impedances deriving from unavoidable step transitions, ports used for pumping and diagnostics, surface roughness, and resistive wall. The results might have an important impact on future technological solutions to be applied to cold bore devices.

  17. A simplified model predicting the weight of the load carrying beam in a wind turbine blade

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Pilgaard

    2016-01-01

    to predict the weight of the load carrying beam when using glassfibre reinforced polymers, carbon fibre reinforced polymers or an aluminium alloy as the construction material. Thereby, it is found that the weight of a glass fibre wind turbine blade is increased from 0.5 to 33 tons when the blade length grows...

  18. Numerical and Exact Solution of Buckling Load For Beam on Elastic Foundation

    Directory of Open Access Journals (Sweden)

    Roland JANČO

    2013-06-01

    Full Text Available In this paper we will be presented the exact solution of buckling load for supported beam on elastic foundation. Exact solution will be compared with numerical solution by FEM in our code in Matlab. Implementation of buckling to FEM will be presented here.

  19. Predicting the behaviour of a wide sandwich beam under pressure loading

    NARCIS (Netherlands)

    Davies, P.; Bigourdan, B.; Chaudot, P.; Choqueuse, D.; Ferreira, A.; Karjalainen, J.P.; Hildebrand, M.; Mustakangas, M.; Gaarder, R.; Carli, F.; Straalen, IJ.J. van; Sargent, J.P.; Adams, R.D.; Broughton, J.; Beevers, A.

    2000-01-01

    This paper presents results from analytical and finite elenent modelling of the response of a wide foam core sandwich beam to uniform pressure loading. New tests have been performed using an image analysis system which allows core shear strain mapping. Predicted panel displacenpnts and strains are c

  20. Development of educational software for beam loading analysis using pen-based user interfaces

    Directory of Open Access Journals (Sweden)

    Yong S. Suh

    2014-01-01

    Full Text Available Most engineering software tools use typical menu-based user interfaces, and they may not be suitable for learning tools because the solution processes are hidden and students can only see the results. An educational tool for simple beam analyses is developed using a pen-based user interface with a computer so students can write and sketch by hand. The geometry of beam sections is sketched, and a shape matching technique is used to recognize the sketch. Various beam loads are added by sketching gestures or writing singularity functions. Students sketch the distributions of the loadings by sketching the graphs, and they are automatically checked and the system provides aids in grading the graphs. Students receive interactive graphical feedback for better learning experiences while they are working on solving the problems.

  1. Beam cavity interaction

    CERN Document Server

    Gamp, A

    2011-01-01

    We begin by giving a description of the rf generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, rf feedback, and feed-forward are described. Examples of digital rf phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  2. SDOF models for reinforced concrete beams under impulsive loads accounting for strain rate effects

    Energy Technology Data Exchange (ETDEWEB)

    Stochino, F., E-mail: fstochino@unica.it [Department of Civil and Environmental Engineering and Architecture, University of Cagliari, Via Marengo 2, 09123 Cagliari (Italy); Carta, G., E-mail: giorgio_carta@unica.it [Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, Via Marengo 2, 09123 Cagliari (Italy)

    2014-09-15

    Highlights: • Flexural failure of reinforced concrete beams under blast and impact loads is studied. • Two single degree of freedom models are formulated to predict the beam response. • Strain rate effects are taken into account for both models. • The theoretical response obtained from each model is compared with experimental data. • The two models give a good estimation of the maximum deflection at collapse. - Abstract: In this paper, reinforced concrete beams subjected to blast and impact loads are examined. Two single degree of freedom models are proposed to predict the response of the beam. The first model (denoted as “energy model”) is developed from the law of energy balance and assumes that the deformed shape of the beam is represented by its first vibration mode. In the second model (named “dynamic model”), the dynamic behavior of the beam is simulated by a spring-mass oscillator. In both formulations, the strain rate dependencies of the constitutive properties of the beams are considered by varying the parameters of the models at each time step of the computation according to the values of the strain rates of the materials (i.e. concrete and reinforcing steels). The efficiency of each model is evaluated by comparing the theoretical results with experimental data found in literature. The comparison shows that the energy model gives a good estimation of the maximum deflection of the beam at collapse, defined as the attainment of the ultimate strain in concrete. On the other hand, the dynamic model generally provides a smaller value of the maximum displacement. However, both approaches yield reliable results, even though they are based on some approximations. Being also very simple to implement, they may serve as an useful tool in practical applications.

  3. Comparative study of beam losses and heat loads reduction methods in MITICA beam source

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, E., E-mail: emanuele.sartori@igi.cnr.it; Agostinetti, P.; Dal Bello, S.; Marcuzzi, D.; Serianni, G.; Veltri, P. [Consorzio RFX, Euratom-ENEA association, C.so Stati Uniti 4, 35127 Padova (Italy); Sonato, P. [Consorzio RFX, Euratom-ENEA association, C.so Stati Uniti 4, 35127 Padova (Italy); Dipartimento di Ingegneria Elettrica, Padova University, Via Gradenigo 6/a, 35131 Padova (Italy)

    2014-02-15

    In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

  4. Comparative study of beam losses and heat loads reduction methods in MITICA beam source

    Science.gov (United States)

    Sartori, E.; Agostinetti, P.; Dal Bello, S.; Marcuzzi, D.; Serianni, G.; Sonato, P.; Veltri, P.

    2014-02-01

    In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

  5. Load Torque Compensator for Model Predictive Direct Current Control in High Power PMSM Drive Systems

    DEFF Research Database (Denmark)

    Preindl, Matthias; Schaltz, Erik

    2010-01-01

    In drive systems the most used control structure is the cascade control with an inner torque, i.e. current and an outer speed control loop. The fairly small converter switching frequency in high power applications, e.g. wind turbines lead to modest speed control performance. An improvement bring......, oscillations in the power etc. For this reason the integrating action of the speed controller must be limited leading to offsets in the speed control and a poor response to load torque variations. For this reason a load torque estimator is proposed in this paper in order to further improve MPDCC dynamic...... the use of a current controller which takes into account the discrete states of the inverter, e.g. DTC or a more modern approach: Model Predictive Direct Current Control (MPDCC). Moreover overshoots and oscillations in the speed are not desired in many applications, since they lead to mechanical stress...

  6. Thermal effect on the dynamic response of axially functionally graded beam subjected to a moving harmonic load

    Science.gov (United States)

    Wang, Yuewu; Wu, Dafang

    2016-10-01

    Dynamic response of an axially functionally graded (AFG) beam under thermal environment subjected to a moving harmonic load is investigated within the frameworks of classical beam theory (CBT) and Timoshenko beam theory (TBT). The Lagrange method is employed to derive the equations of thermal buckling for AFG beam, and then with the critical buckling temperature as a parameter the Newmark-β method is adopted to evaluate the dynamic response of AFG beam under thermal environments. Admissible functions denoting transverse displacement are expressed in simple algebraic polynomial forms. Temperature-dependency of material constituent is considered. The rule of mixture (Voigt model) and Mori-Tanaka (MT) scheme are used to evaluate the beam's effective material properties. A ceramic-metal AFG beam with immovable boundary condition is considered as numerical illustration to show the thermal effects on the dynamic behaviors of the beam subjected to a moving harmonic load.

  7. EXPERIMENTAL STUDY ON CRACK CURVING PROPAGATION IN BENDING BEAMS UNDER IMPULSIVE LOAD

    Institute of Scientific and Technical Information of China (English)

    Fang Jing; Yao Xuefeng; Xiong Chunyang

    2000-01-01

    Dynamic fracture behaviour of crack curving in bent beams has been investigated.In order to understand the propagation mechanism of such cracks under impact,an experimental method is used that combines dynamic photoelasticity with dynamic caustics to study the interaction of the flexural waves and the crack.From the state change of the transient stresses in polymer specimen,the curving fracture in the impulsively loaded beams is analyzed.The dynamic responses of crack tips are evaluated by the stress intensity factors for the cracks running in varying curvature paths under bending stress wave.

  8. Characterization of Fogging and Develop-Loading Effects in Electron-Beam Direct-Writing Technology

    Science.gov (United States)

    Kon, Jun-ichi; Kojima, Yoshinori; Takahashi, Yasushi; Maruyama, Takashi; Sugatani, Shinji

    2012-06-01

    We investigated long-range critical dimension (CD) error factors, such as fogging and develop loading, to improve CD uniformity in electron-beam direct-writing (EBDW) technology. It was found that the impact of both effects reached 20 mm and the CD of the monitor pattern decreased by no less than 10%. Fogging and develop loading were separated by comparing the newly designed test patterns that were exposed using both EB and a krypton-fluoride excimer laser. We confirmed that the impact of fogging and develop loading by arranging dummy patterns with a density of 40% was estimated to be +8.9 and -18.9% in the CD, respectively. Based on success in separating each effect, fogging and develop loading were decreased by applying an antistatic agent and multipuddle development, respectively.

  9. A hybrid approach to analyse a beam-soil structure under a moving random load

    Science.gov (United States)

    Si, L. T.; Zhao, Y.; Zhang, Y. H.; Kennedy, D.

    2016-11-01

    To study the stochastic response of a beam-soil structure under a moving random load, a hybrid approach based on the pseudo-excitation method and the wavelet method is proposed. Using the pseudo-excitation method, the non-stationary random vibration analysis is transformed into a conventional moving harmonic load problem. Analytical solutions of the power spectral density and standard deviation of vertical displacement are derived in an integral form. However, the integrand is singular and highly oscillatory, and the computational time is an important consideration because a large number of frequency points must be computed. To calculate the response accurately and efficiently, a wavelet approach is introduced. Numerical results show that the frequency band which brings the most significant response is dependent on the load velocity. The hybrid method provides a useful tool to estimate the ground vibration caused by traffic loads.

  10. High intensity single bunch operation with heavy periodic transient beam loading in wide band rf cavities

    Science.gov (United States)

    Tamura, Fumihiko; Hotchi, Hideaki; Schnase, Alexander; Yoshii, Masahito; Yamamoto, Masanobu; Ohmori, Chihiro; Nomura, Masahiro; Toda, Makoto; Shimada, Taihei; Hasegawa, Katsushi; Hara, Keigo

    2015-09-01

    The rapid cycling synchrotron (RCS) in the Japan Proton Accelerator Research Complex (J-PARC) was originally designed to accelerate two high intensity bunches, while some of neutron experiments in the materials and life science experimental facility and a muon experiment using main ring beams require a single bunch operation mode, in which one of the two rf buckets is filled and the other is empty. The beam intensity in the single bunch operation has been limited by longitudinal beam losses due to the rf bucket distortions by the wake voltage of the odd harmonics (h =1 ,3 ,5 ) in the wide band magnetic alloy cavities. We installed an additional rf feedforward system to compensate the wake voltages of the odd harmonics (h =1 ,3 ,5 ). The additional system has a similar structure as the existing feedforward system for the even harmonics (h =2 ,4 ,6 ). We describe the function of the feedforward system for the odd harmonics, the commissioning methodology, and the commissioning results. The longitudinal beam losses during the single bunch acceleration disappeared with feedforward for the odd harmonics. We also confirmed that the beam quality in the single bunch acceleration are similar to that of the normal operation with two bunches. Thus, high intensity single bunch acceleration at the intensity of 2.3 ×1013 protons per bunch has been achieved in the J-PARC RCS. This article is a follow-up of our previous article, Phys. Rev. ST Accel. Beams 14, 051004 (2011). The feedforward system extension for single bunch operation was successful.

  11. Helicopter Rotor Load Prediction Using a Geometrically Exact Beam with Multicomponent Model

    DEFF Research Database (Denmark)

    Lee, Hyun-Ku; Viswamurthy, S.R.; Park, Sang Chul;

    2010-01-01

    In this paper, an accurate structural dynamic analysis was developed for a helicopter rotor system including rotor control components, which was coupled to various aerodynamic and wake models in order to predict an aeroelastic response and the loads acting on the rotor. Its blade analysis was based...... on an intrinsic formulation of moving beams implemented in the time domain. The rotor control system was modeled as a combination of rigid and elastic components. A multicomponent analysis was then developed by coupling the beam finite element model with the rotor control system model to obtain a complete rotor-blade/control...... rotor-blade/control-system model was loosely coupled with various inflow and wake models in order to simulate both hover and forward-flight conditions. The resulting rotor blade response and pitch link loads are in good agreement with those predicted byCAMRADII. The present analysis features both model...

  12. Numerical Behavior Reproduction of a Truss Structure and Beam, Subjected to Concentrated Load

    Directory of Open Access Journals (Sweden)

    Nedelcu Dorian

    2010-10-01

    Full Text Available The paper deals with a numerical reproduction of a real experiment consisting of the same restraints and concentrated load applied to a truss structure and beam; the numerical reproduction was performed with SolidWorks software, where both geometrical reconstruction and finite element analysis were made. The goals of the analysis was to compare the numerical with experimental results and to evaluate the best structure using the structural response criteria.

  13. Optimal Distribution of Viscoelastic Dampers under Elastic Finite Beam under Moving Load

    Directory of Open Access Journals (Sweden)

    Khurshudyan Am. Zh.

    2014-09-01

    Full Text Available The problem of viscoelastic dampers optimal distribution function determination is investigated under simply supported elastic beam of finite length, subjected to a moving load with constant intensity, moving along the beam with constant velocity. Our main aim is the dampers optimal distribution function determination, and optimality criterion– the density of that distribution. Problem is mathematically formulated as initial–boundary problem for bilinear wave equation with variable controllable coefficient. Application of Bubnov–Gelerkin procedure allow us to reduce solution of the problem to finite–dimensional moments problem, which is resolved explicitly. It is proved, that optimal in mentioned sense is dampers discrete (pointwise distribution. Approximating function of beam deflection is deter-mined. Results of numerical calculations are presented.

  14. Transient behaviour of a ``beam loaded`` prebuncher cavity and linac structure

    Energy Technology Data Exchange (ETDEWEB)

    Messina, Giovanni; Picardi, Luigi; Ronsivalle, Concetta; Vignati, Angelo [ENEA, Centro Ricerche Frascati, Rome (Italy)

    1997-03-01

    They present the evaluation of the effect of the beam loading on the time response of a 3 GHz prebuncher cavity to the generator and to an input 120 deg chopped electron beam for two different cavity materials. The lumped-element representation of the cavity as a parallel RLC circuit is used which allows to compute also the sensitivity of the prebuncher voltage amplitude and phase with respect to beam current fluctuations. The analysis has been extended to the transient behaviour of a linac positioned after the prebuncher cavity. The consequences of the computation results on the application of a chopper-prebuncher system in a linac devoted to the MUH FEL experiment are discussed.

  15. A closed-form solution to a viscoelastically supported Timoshenko beam under harmonic line load

    Science.gov (United States)

    Luo, W. L.; Xia, Y.; Zhou, X. Q.

    2016-05-01

    This study aims to formulate a closed-form solution to a viscoelastically supported Timoshenko beam under a harmonic line load. The differential governing equations of motion are converted into algebraic equations by assuming the deflection and rotation of the beam in harmonic forms with respect to time and space. The characteristic equation is biquadratic and thus contains 14 explicit roots. These roots are then substituted into Cauchy's residue theorem; consequently, five forms of the closed-form solution are generated. The present solution is consistent with that of an Euler-Bernoulli beam on a Winkler foundation, which is a special case of the present problem. The current solution is also verified through numerical examples.

  16. Fatigue Strain and Damage Analysis of Concrete in Reinforced Concrete Beams under Constant Amplitude Fatigue Loading

    Directory of Open Access Journals (Sweden)

    Fangping Liu

    2016-01-01

    Full Text Available Concrete fatigue strain evolution plays a very important role in the evaluation of the material properties of concrete. To study fatigue strain and fatigue damage of concrete in reinforced concrete beams under constant amplitude bending fatigue loading, constant amplitude bending fatigue experiments with reinforced concrete beams with rectangular sections were first carried out in the laboratory. Then, by analyzing the shortcomings and limitations of existing fatigue strain evolution equations, the level-S nonlinear evolution model of fatigue strain was constructed, and the physical meaning of the parameters was discussed. Finally, the evolution of fatigue strain and fatigue damage of concrete in the compression zone of the experimental beam was analyzed based on the level-S nonlinear evolution model. The results show that, initially, fatigue strain grows rapidly. In the middle stages, fatigue strain is nearly a linear change. Because the experimental data for the third stage are relatively scarce, the evolution of the strain therefore degenerated into two phases. The model has strong adaptability and high accuracy and can reflect the evolution of fatigue strain. The fatigue damage evolution expression based on fatigue strain shows that fatigue strain and fatigue damage have similar variations, and, with the same load cycles, the greater the load level, the larger the damage, in line with the general rules of damage.

  17. Simulation of Fatigue Stiffness Degradation in Prestressed Concrete Beams under Cyclic Loading

    Institute of Scientific and Technical Information of China (English)

    Junqing Lei; Shanshan Cao; Guoshan Xu; Yun Xiao

    2016-01-01

    In order to investigate and research the fatigue cracking of prestressed concrete fatigue properties and loading and stiffness degeneration process, cyclic loading tests were carried out on six prestressed concrete beams and the stiffness degradation under fatigue was investigated. A simulation model of stiffness degradation is proposed based on the stiffness analysis of the fatigue⁃damaged section. The elastic modulus of damaged concrete and the effective residual area of steel were introduced as well as an adjusted three⁃stage concrete fatigue damage evolution model. The strip method was used to analyze concrete damage due to changing stress along the depth of the beam section. The simulation and test results were compared and a method of predicting fatigue deflection was presented based on the simulation model. The predicted results were compared with that of the neural network method. It is in good agreement for the simulation results with the test results. It is only less than 5% error for the simulation model which can reveal the two⁃stage degradation of prestressed concrete beams under cyclic loading. It is more precise for the simulation prediction method under proper conditions.

  18. Second-Order Nonlinear Analysis of Steel Tapered Beams Subjected to Span Loading

    Directory of Open Access Journals (Sweden)

    Ali Hadidi

    2014-03-01

    Full Text Available A second-order elastic analysis of tapered steel members with I-shaped sections subjected to span distributed and concentrated loadings is developed. Fixed end forces and moments as well as exact stiffness matrix of tapered Timoshenko-Euler beam are obtained with exact geometrical properties of sections. The simultaneous action of bending moment, shear, and axial force including P−δ effects is also considered in the analysis. A computer code has been developed in MATLAB software using a power series method to solve governing second-order differential equation of equilibrium with variable coefficients for beams with distributed span loading. A generalized matrix condensation technique is then utilized for analysis of beams with concentrated span loadings. The accuracy and efficiency of the results of the proposed method are verified through comparing them to those obtained from other approaches such as finite element methods, which indicates the robustness and time saving of this method even for large scale frames with tapered members.

  19. Analysis of the Dynamic Response in Blast-Loaded CFRP-Strengthened Metallic Beams

    Directory of Open Access Journals (Sweden)

    Zhenyu Wang

    2013-01-01

    Full Text Available Carbon fiber-reinforced polymer composites (CFRPs are good candidates in enhancing the blast resistant performance of vulnerable public buildings and in reinforcing old buildings. The use of CFRP in retrofitting and strengthening applications is traditionally associated with concrete structures. Nevertheless, more recently, there has been a remarkable aspiration in strengthening metallic structures and components using CFRP. This paper presents a relatively simple analytical solution for the deformation and ultimate strength calculation of hybrid metal-CFRP beams when subjected to pulse loading, with a particular focus on blast loading. The analytical model is based on a full interaction between the metal and the FRP and is capable of producing reasonable results in a dynamic loading scenario. A nonlinear finite element (FE model is also developed to reveal the full dynamic behavior of the CFRP-epoxy-steel hybrid beam, considering the detailed effects, that is, large strains, high strain rates in metal, and different failure modes of the hybrid beam. Experimental results confirm the analytical and the FE results and show a strong correlation.

  20. Large deflections of non-prismatic nonlinearly elastic cantilever beams subjected to non-uniform continuous load and a concentrated load at the free end

    Institute of Scientific and Technical Information of China (English)

    Miha Brojan; Matjaz Cebron; Franc Kosel

    2012-01-01

    This work studies large deflections of slender,non-prismatic cantilever beams subjected to a combined loading which consists of a non-uniformly distributed continuous load and a concentrated load at the free end of the beam.The material of the cantilever is assumed to be nonlinearly elastic.Different nonlinear relations between stress and strain in tensile and compressive domain are considered.The accuracy of numerical solutions is evaluated by comparing them with results from previous studies and with a laboratory experiment.

  1. Balance Component Decomposition and Compensation Method for Unbalanced Load%不平衡负载的平衡分量法分解及补偿方法

    Institute of Scientific and Technical Information of China (English)

    胡应宏; 王建赜; 任佳佳; 纪延超

    2012-01-01

    In order to make a better compensation for the three-phase unbalanced load, the unbalanced load was analyzed and a method of reactive compensation admittance calculation based on balance component method was proposed. Any neutral non-grounded three-phase load can be decomposed into a group of balanced load and single line load, and the load compensation admittance can be obtained by the decomposition of the three-phase unbalance load. The load compensation admittance calculation can be divided into three parts, the power factor compensation for the balanced load and the single line load together with the balanced compensation for the single line resistive load. Then, the ideal Steinmetz compensation network algorithm was amended under the condition of asymmetric voltage. A freedom degree existed in this case, and the asymmetry voltage compensation admittance can be accurately calculated according to the control objectives and the revised ideal compensation network calculation method. The rationality and validity of the method was verified using example and simulation. Compared with existing methods, the proposed method has easy calculation and convenient realization.%为了更好地对三相不平衡负荷进行平衡化补偿,对不平衡负载进行详细分析,提出一种新的基于平衡分量法的无功补偿导纳计算方法.首先,将任何中性点不接地的三相负载分解为平衡负载和一个线间负载之和,通过将三相负载进行分解,可以得到负载所需要补偿的导纳值.补偿导纳的计算可分为平衡负载功率因数补偿、线间负载功率因数补偿以及线间线阻性负载平衡化补偿3部分.然后,对系统电压不对称时的Steinmetz.理想补偿网络算法进行修正,根据控制目标和修正后的理想补偿网络算法,计算出系统电压不对称时所需的补偿导纳值.通过算例、仿真分析及实验验证,证明了所提无功补偿导纳计算方法的合理性和正确性,该方

  2. Application of a Reinforced Self-Compacting Concrete Jacket in Damaged Reinforced Concrete Beams under Monotonic and Repeated Loading

    Directory of Open Access Journals (Sweden)

    Constantin E. Chalioris

    2013-01-01

    Full Text Available This paper presents the findings of an experimental study on the application of a reinforced self-compacting concrete jacketing technique in damaged reinforced concrete beams. Test results of 12 specimens subjected to monotonic loading up to failure or under repeated loading steps prior to total failure are included. First, 6 beams were designed to be shear dominated, constructed by commonly used concrete, were initially tested, damaged, and failed in a brittle manner. Afterwards, the shear-damaged beams were retrofitted using a self-compacting concrete U-formed jacket that consisted of small diameter steel bars and U-formed stirrups in order to increase their shear resistance and potentially to alter their initially observed shear response to a more ductile one. The jacketed beams were retested under the same loading. Test results indicated that the application of reinforced self-compacting concrete jacketing in damaged reinforced concrete beams is a promising rehabilitation technique. All the jacketed beams showed enhanced overall structural response and 35% to 50% increased load bearing capacities. The ultimate shear load of the jacketed beams varied from 39.7 to 42.0 kN, whereas the capacity of the original beams was approximately 30% lower. Further, all the retrofitted specimens exhibited typical flexural response with high values of deflection ductility.

  3. Researches on Fuzzy Creep Compensation of Load Cell%称重传感器蠕变的模糊补偿方法研究

    Institute of Scientific and Technical Information of China (English)

    朱子健; 陈仁文

    2002-01-01

    本文介绍了对传感器蠕变进行补偿的新方法,首次引入模糊识别的方法来确定载荷的变化情况,该方法可实现蠕变实时精确补偿,简便易行,避免了繁琐的传感器蠕变模型的建立和实现过程.实验证明这种方法精度很好.%Creep is a critical specification of load cell. Based on the analysis of creep, a new compensation technique, fuzzy creep compensation, is presented in this paper. It firstly introduces the fuzzy recognition to determine loading situations. Compared to the other compensation methods, fuzzy creep compensation can avoid the complicated modeling of creep performance, and it is also proved to be an efficient and simple approach to improve the accuracy of load cell by experiments.

  4. 适用于配网冲击性负荷补偿的链式D-STATCOM%Cascade distribution static synchronous compensator for impulse load compensation in the distribution network

    Institute of Scientific and Technical Information of China (English)

    范瑞祥; 吴素农; 孙旻; 宋强

    2011-01-01

    A relocatable cascade distribution static synchronous compensator (D-STATCOM) is presented to meet the power quality requirement of distribution network when impulse loads connecting. Operating with switching capacitor branch, the compensator realizes the synchronous compensation of reactive power. As the example of the application in Jiangxi power grid, the compensation requirement of electric arc furnace which is typical impulse load was analyzed. With field wave recording data and distribution system parameter, simulation model was built. By using frequency dividing coordination control method, the active power compensator can work with switching capacitor branch perfectly. It reduced the dynamic capacity requirement of the compensating system effectively. The active power compensator realized moveable by accepting the cascade main circuit and modularization design. The field application plan of the equipment was put forward. The system parameter configuration method and principle were also given in detail. The operation effect shows that with the fast responding speed and working stability, the equipment can meet the compensation requirement of Var shock in distribution network.%针对冲击性负荷接入配电网后带来的电能质量问题,提出一种基于链式结构的静止同步补偿器(D-STATCOM)的移动型并联有源补偿装置,与固定电容补偿装置形成良好配合,实现了无功的实时动态补偿.以江西电网实例应用为基础,分析以电弧炉为代表的典型冲击性负荷补偿的具体需求,结合现场录波数据和配电系统参数建立仿真模型,应用分频协调控制策略与固定补偿支路形成良好配合,降低了动态容量需求,采用链式主电路和模块化设计实现了有源型补偿装置D-STATCOM的移动化.提出了装置的现场应用方案,给出了基本工程参数的配置方法与原则.投运效果表明,装置响应迅速,运行稳定,能够满足配电网动态无功冲击补偿的要求.

  5. Load compensation research on twice-tension for loop anchor cable of inner lining in Yellow River-crossing tunnel

    Institute of Scientific and Technical Information of China (English)

    Yin Juan; Cao Shengrong; Qin Gan; Yang Fan

    2014-01-01

    The load compensation equipment for anchor cable named low retraction prestressed anchorage sys-tem with twice-tension (referred to as twice-tension anchorage system) is proposed in the paper. Calculation re-sults of loop anchorage prestressing loss (PL) values of inner lining(IL)in Yellow River-crossing tunnel under two anchorage systems,including twice-tension anchorage system and HM(Chinese transliteration is huan-mao)anchorage system,are introduced. The software ANSYS is selected to realize the three-dimensional (3D) finite element modeling to accomplish simulation and calculation works under the two anchorage systems,re-spectively. Stress processes of IL under the two working conditions,of which one is completed cable tensioning (CCT) and the other is water in the tunnel with the designed water pressure (DWP),are contrasted and ana-lyzed. Impacts of prestressing forces of anchor cables on structural safety under the two anchorage systems are contrasted. The calculation results show that the twice-tension anchorage system can reduce PL effectively and then increase prestresses of wall concrete(WC). Meanwhile,the anchorage system has the advantages of im-proving security and stability of tunnel structure,reducing project costs and saving steel consumption. The re-search work is available to related design and construction of anchor cable,and is worthy of promotion and ap-plication.

  6. A simplified model predicting the weight of the load carrying beam in a wind turbine blade

    Science.gov (United States)

    Mikkelsen, Lars P.

    2016-07-01

    Based on a simplified beam model, the loads, stresses and deflections experienced by a wind turbine blade of a given length is estimated. Due to the simplicity of the model used, the model is well suited for work investigating scaling effects of wind turbine blades. Presently, the model is used to predict the weight of the load carrying beam when using glass fibre reinforced polymers, carbon fibre reinforced polymers or an aluminium alloy as the construction material. Thereby, it is found that the weight of a glass fibre wind turbine blade is increased from 0.5 to 33 tons when the blade length grows from 20 to 90 m. In addition, it can be seen that for a blade using glass fibre reinforced polymers, the design is controlled by the deflection and thereby the material stiffness in order to avoid the blade to hit the tower. On the other hand if using aluminium, the design will be controlled by the fatigue resistance in order to making the material survive the 100 to 500 million load cycles experience of the wind turbine blade throughout the lifetime. The aluminium blade is also found to be considerably heavier compared with the composite blades.

  7. Temperature error compensation for load cell based on RBFNN*%基于RBFNN的称重传感器温度误差补偿

    Institute of Scientific and Technical Information of China (English)

    杨进宝; 倪芳英; 张建军

    2011-01-01

    Load cell has nonlinear error because of different ambient temperature in work, and it is necessary to compensate. The principle of temperature error of load cell is illustrated, and a method for compensating this error based on radial basis function neural network (RBFNN) is proposed. The training algorithm of RBFNN is described. Using this proposed temperature error compensation method and the load cell which the weighing range is 100 kg,the experiments are implemented under 0 ~60℃. The results show that temperature errors of load cell are decreased, and its weighing accuracy is increased.%称重传感器存在因环境温度不同导致的非线性误差,需要进行补偿.阐述了称重传感器的温度误差机理,提出了一种基于径向基函数神经网络(RBFNN)的称重传感器温度误差补偿方法,并给出了训练算法.采用该方法,利用量程为100kg的称重传感器,在0~60℃范围内进行温度误差补偿实验.实验表明:采用这种方法补偿后,称重传感器温度误差大大减少,提高了称重准确度.

  8. Analytical solution and semi-analytical solution for anisotropic functionally graded beam subject to arbitrary loading

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Analytical and semi-analytical solutions are presented for anisotropic functionally graded beams subject to an arbitrary load,which can be expanded in terms of sinusoidal series.For plane stress problems,the stress function is assumed to consist of two parts,one being a product of a trigonometric function of the longitudinal coordinate(x) and an undetermined function of the thickness coordinate(y),and the other a linear polynomial of x with unknown coefficients depending on y.The governing equations satisfied by these y-dependent functions are derived.The expressions for stresses,resultant forces and displacements are then deduced,with integral constants determinable from the boundary conditions.While the analytical solution is derived for the beam with material coefficients varying exponentially or in a power law along the thickness,the semi-analytical solution is sought by making use of the sub-layer approximation for the beam with an arbitrary variation of material parameters along the thickness.The present analysis is applicable to beams with various boundary conditions at the two ends.Three numerical examples are presented for validation of the theory and illustration of the effects of certain parameters.

  9. Oscillations of a Beam on a Non-Linear Elastic Foundation under Periodic Loads

    Directory of Open Access Journals (Sweden)

    Donald Mark Santee

    2006-01-01

    Full Text Available The complexity of the response of a beam resting on a nonlinear elastic foundation makes the design of this structural element rather challenging. Particularly because, apparently, there is no algebraic relation for its load bearing capacity as a function of the problem parameters. Such an algebraic relation would be desirable for design purposes. Our aim is to obtain this relation explicitly. Initially, a mathematical model of a flexible beam resting on a non-linear elastic foundation is presented, and its non-linear vibrations and instabilities are investigated using several numerical methods. At a second stage, a parametric study is carried out, using analytical and semi-analytical perturbation methods. So, the influence of the various physical and geometrical parameters of the mathematical model on the non-linear response of the beam is evaluated, in particular, the relation between the natural frequency and the vibration amplitude and the first period doubling and saddle-node bifurcations. These two instability phenomena are the two basic mechanisms associated with the loss of stability of the beam. Finally Melnikov's method is used to determine an algebraic expression for the boundary that separates a safe from an unsafe region in the force parameters space. It is shown that this can be used as a basis for a reliable engineering design criterion.

  10. Analytical solution and semi-analytical solution for anisotropic functionally graded beam subject to arbitrary loading

    Institute of Scientific and Technical Information of China (English)

    HUANG DeJin; DING Haodiang; CHEN WeiQiu

    2009-01-01

    Analytical and semi-analytical solutions are presented for anisotropic functionally graded beams sub-ject to an arbitrary load, which can be expanded in terms of sinusoidal series. For plane stress prob-lems, the stress function is assumed to consist of two parts, one being a product of a trigonometric function of the longitudinal coordinate (x) and an undetermined function of the thickness coordinate (y), and the other a linear polynomial of x with unknown coefficients depending on y. The governing equa-tions satisfied by these y-dependent functions are derived. The expressions for stresses, resultant forces and displacements are then deduced, with integral constants determinable from the boundary conditions. While the analytical solution is derived for the beam with material coefficients varying exponentially or in a power law along the thickness, the semi-analytical solution is sought by making use of the sub-layer approximation for the beam with an arbitrary variation of material parameters along the thickness. The present analysis is applicable to beams with various boundary conditions at the two ends. Three numerical examples are presented for validation of the theory and illustration of the effects of certain parameters.

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

    DEFF Research Database (Denmark)

    Miranda, Erik; Thomsen, Jon Juel

    1998-01-01

    The study sets up a simple model for predicting vibration induced sliding of mass, and provides quantitative experimental evidence for the validity of the model. The results lend confidence to recent theoretical developments on using vibration induced sliding for passive vibration damping......, and contributes to a further understanding of this nonlinear phenomenon. A mathematical model is set up to describe vibration induced sliding for a base-excited cantilever beam with a spring-loaded pointmass. Approximations simplify the model into two nonlinear ordinary differential equations, describing motions...... of the system at near-resonant excitation of a single beam mode. This simplified model is studied numerically and analytically, and tested against laboratory experiments. The experiments provide evidence that the simplified mathematical model retains those features of the real system that are necessary...

  12. Neutron spectra at two beam ports of a TRIGA Mark III reactor loaded with HEU fuel.

    Science.gov (United States)

    Vega-Carrillo, H R; Hernández-Dávila, V M; Aguilar, F; Paredes, L; Rivera, T

    2014-01-01

    The neutron spectra have been measured in two beam ports, one radial and another tangential, of the TRIGA Mark III nuclear reactor from the National Institute of Nuclear Research in Mexico. Measurements were carried out with the reactor core loaded with high enriched uranium fuel. Two reactor powers, 5 and 10 W, were used during neutron spectra measurements using a Bonner sphere spectrometer with a (6)LiI(Eu) scintillator and 2, 3, 5, 8, 10 and 12 in.-diameter high-density polyethylene spheres. The neutron spectra were unfolded using the NSDUAZ unfolding code. For each spectrum total flux, mean energy and ambient dose equivalent were determined. Measured spectra show fission, epithermal and thermal neutrons, being harder in the radial beam port.

  13. Finite Element Modelling of Infinite Euler Beams on Kelvin Foundations Exposed to Moving Loads in Convected Co-ordinates

    DEFF Research Database (Denmark)

    Andersen, Lars; Nielsen, Søren R.K.; Kirkegaard, Poul Henning

    2001-01-01

    The paper deals with the finite element method (FEM) solution of the problem with loads moving uniformly along an infinite Euler beam supported by a linear elastic Kelvin foundation with linear viscous damping. Initially, the problem is formulatedin a moving co-ordinate system following the load ...

  14. Compensating the Electron Beam Energy Spread by the Natural Transverse Gradient of Laser Undulator in All-Optical X-ray Sources

    CERN Document Server

    Zhang, Tong; Deng, Haixiao; Wang, Dong; Dai, Zhimin; Zhao, Zhentang

    2013-01-01

    All-optical schemes provide a potential to dramatically cut off the size and cost of x-ray light sources to the university-laboratory scale, with the combination of the laser-plasma accelerator and the laser undulator. However, the large longitudinal energy spread of the electron beam from laser-plasma accelerator may hinder the way to high brightness of these all-optical light sources. In this letter, the beam energy spread effect is proposed to be significantly compensated by the natural transverse gradient of a laser undulator when properly dispersing the electron beam transversely. Theoretical analysis and numerical simulations on conventional laser-Compton scattering sources and high-gain all-optical x-ray free-electron lasers with the electron beams from laser-plasma accelerators are presented.

  15. Analytical solution for functionally graded anisotropic cantilever beam under thermal and uniformly distributed load

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The bending problem of a functionally graded anisotropic cantilever beam subjected to thermal and uniformly distributed load is investigated, with material parameters being arbitrary functions of the thickness coordinate. The heat conduction problem is treated as a 1D problem through the thickness. Based on the elementary formulations for plane stress problem, the stress function is assumed to be in the form of polynomial of the longitudinal coordinate variable, from which the stresses can be derived.The stress function is then determined completely with the compatibility equation and boundary conditions. A practical example is presented to show the application of the method.

  16. ANALYTICAL SOLUTION FOR FIXED-FIXED ANISOTROPIC BEAM SUBJECTED TO UNIFORM LOAD

    Institute of Scientific and Technical Information of China (English)

    DING Hao-jiang; HUANG De-jin; WANG Hui-ming

    2006-01-01

    The analytical solutions of the stresses and displacements were obtained for fixed-fixed anisotropic beams subjected to uniform load. A stress function involving unknown coefficients was constructed, and the general expressions of stress and displacement were obtained by means of Airy stress function method. Two types of the description for the fixed end boundary condition were considered. The introduced unknown coefficients in stress function were determined by using the boundary conditions. The analytical solutions for stresses and displacements were finally obtained. Numerical tests show that the analytical solutions agree with the FEM results. The analytical solution supplies a classical example for the elasticity theory.

  17. Analytical solution for functionally graded anisotropic cantilever beam subjected to linearly distributed load

    Institute of Scientific and Technical Information of China (English)

    HUANG De-jin; DING Hao-jiang; CHEN Wei-qiu

    2007-01-01

    The bending problem of a functionally graded anisotropic cantilever beam subjected to a linearly distributed load is investigated. The analysis is based on the exact elasticity equations for the plane stress problem. The stress function is introduced and assumed in the form of a polynomial of the longitudinal coordinate. The expressions for stress components are then educed from the stress function by simple differentiation.The stress function is determined from the compatibility equation as well as the boundary conditions by a skilful deduction. The analytical solution is compared with FEM calculation, indicating a good agreement.

  18. Beam Test of a Dielectric Loaded High Pressure RF Cavity for Use in Muon Cooling Channels

    Energy Technology Data Exchange (ETDEWEB)

    Freemire, Ben [IIT, Chicago; Bowring, Daniel [Fermilab; Kochemirovskiy, Alexey [Chicago U.; Moretti, Alfred [Fermilab; Peterson, David [Fermilab; Tollestrup, Alvin [Fermilab; Torun, Yagmur [IIT, Chicago; Yonehara, Katsuya [Fermilab

    2016-06-01

    Bright muon sources require six dimensional cooling to achieve acceptable luminosities. Ionization cooling is the only known method able to do so within the muon lifetime. One proposed cooling channel, the Helical Cooling Channel, utilizes gas filled radio frequency cavities to both mitigate RF breakdown in the presence of strong, external magnetic fields, and provide the cooling medium. Engineering constraints on the diameter of the magnets within which these cavities operate dictate the radius of the cavities be decreased at their nominal operating frequency. To accomplish this, one may load the cavities with a larger dielectric material. A 99.5% alumina ring was inserted in a high pressure RF test cell and subjected to an intense proton beam at the MuCool Test Area at Fermilab. The results of the performance of this dielectric loaded high pressure RF cavity will be presented.

  19. In situ stress monitoring of the concrete beam under static loading with cement-based piezoelectric sensors

    Science.gov (United States)

    Dong, Biqin; Liu, Yuqing; Qin, Lei; Wang, Yaocheng; Fang, Yuan; Xing, Feng; Chen, Xianchuan

    2015-10-01

    In this paper, the application of a novel cement-based piezoelectric ceramic sensor is stated for the in situ stress monitoring of the reinforced concrete beam under static loading. Smart beam composite structures were designed and characterised by a range of experimental methods. Finite element analysis is used to analyse the mechanical response of the concrete beam under static loading. The results show that the mechanical-electrical response of sensors embedded in reinforced concrete beams follows a linear relationship under various loading conditions. The sensors are able to record the stress history of the beam under static loads. Moreover, the measured stress data agree well with the simulated results and the smart structures are found to be capable of reliably monitoring the response of a beam during stress testing for static loading modes to real concrete structures. The study indicates that such cement-based piezoelectric composites have a high feasibility and applicability to the in situ stress monitoring of reinforced concrete structures.

  20. Method for adaptive compensation of load cell's nonlinear error%称重传感器非线性误差自适应补偿方法

    Institute of Scientific and Technical Information of China (English)

    杨进宝; 汪鲁才

    2011-01-01

    The nonlinear error of load cell is not same in weight range. The character of load cell's nonlinear error is formulated and a method for adaptive compensation is proposed. The nonlinear error compensation network based on Radial Basis Function Neural Network(RBFNN) is used in upper limit of load cell' weighing range, the digital filter is applied in the low limit range,and the load cell is not compensated in the middle range.The adaptive selective network is use to choose the subnet for error compensation.The experimental results show that the maximum relative error of load cell with this method respectively drops from 0.2% in its lower interval scale,0.4% in its middle interval scale, and 1.37% in its upper interval scale without compensation to 0.16%,0.04%,and 0.07% after compensation,and its weighing result is more accurate.%额定量程内称重传感器的非线性误差不同,为此阐述了称重传感器的非线性误差特性,提出了一种非线性误差自适应分.段补偿方法:在额定量程的上限区,采用基于径向基函数神经网络(RBFNN)的补偿网络完成传感器非线性误差补偿;在下限区,采用数字滤波器完成非线性误差补偿;在中间区,传感器不补偿.同时利用自适应选择网络,完成了分段补偿的选择.实验表明,采用这种方法补偿后的称重传感器下限区、中间区与上限区的最大相对误差分别由补偿前的0.2%、0.4%,1.37%下降到0.16%,0.04%、0.07%,补偿效果明显.

  1. 农村电网不对称负荷补偿方法研究%Study on compensation method of unbalanced load in rural power grid

    Institute of Scientific and Technical Information of China (English)

    房俊龙; 于洪涛; 马文川; 蔡银哿; 杨庆忠; 杨国良

    2014-01-01

    The paper proposed TCR type static var compensator based on Steinmetz theory which it could be used in the rural power grid, it could compensate unbalanced load and improve power factor in the meantime. The results showed that method could effectively make three-phase load balance, while increasing the power factor, had a certain theoretical and application value.%文章提出在农村电网中采用基于Steinmetz电路理论的TCR型静止无功补偿器,平衡三相不对称负荷,提高系统功率因数。仿真验证结果表明,该方法能使三相负荷平衡,提高功率因数,具有一定理论意义及应用价值。

  2. The effect of transverse shear on the face sheets failure modes of sandwich beams loaded in three points bending

    Directory of Open Access Journals (Sweden)

    BOUROUIS FAIROUZ

    2012-04-01

    Full Text Available Sandwich beams loaded in three points bending may fail in several ways including tension or compression failure of facings. In this paper , The effect of the transverse shear on the face yielding and face wrinkling failure modes of sandwich beams loaded in three points bending have been studied, the beams were made of various composites materials carbon/epoxy, kevlar/epoxy, glass/epoxy at sequence [+θ/-θ]3s, [0°/90°]3s. . The stresses in the face were calculated using maximum stress criterion and the simple beam theory. The obtained different results show that the sandwich beams with carbon/epoxy, and glass/epoxy face sheets are the best materials, inreturn the kevlar /epoxy facing characterised by low resistance of transverse shear in compression and tensile.

  3. Improving the accuracy of derivation of the Williams’ series parameters under mixed (I+II) mode loading by compensation of measurement bias in the stress field components data

    Science.gov (United States)

    Lychak, Oleh V.; Holyns'kiy, Ivan S.

    2016-12-01

    A new method for compensation of bias in the stress field components measurement data used for Williams’ series parameters derivation was presented. Essential increase of accuracy of derivation of SIF-related leading terms in series under mixed (I+II) mode loading was demonstrated. It was shown that a relatively low value of bias in the stress field components data error could result in the essential deviation of the values of derived Williams’ coefficients and the crack tip coordinates.

  4. Development of chloride-induced corrosion in pre-cracked RC beams under sustained loading: Effect of load-induced cracks, concrete cover, and exposure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Linwen [Université de Toulouse, UPS, INSA, LMDC, Toulouse (France); Université de Sherbrooke, Quebec (Canada); François, Raoul, E-mail: raoul.francois@insa-toulouse.fr [Université de Toulouse, UPS, INSA, LMDC, Toulouse (France); Dang, Vu Hiep [Hanoi Architectural University, Faculty of Civil Engineering, Hanoi (Viet Nam); L' Hostis, Valérie [CEA Saclay, CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, Gif-sur-Yvette (France); Gagné, Richard [Université de Sherbrooke, Quebec (Canada)

    2015-01-15

    This paper deals with corrosion initiation and propagation in pre-cracked reinforced concrete beams under sustained loading during exposure to a chloride environment. Specimen beams that were cast in 2010 were compared to specimens cast in 1984. The only differences between the two sets of beams were the casting direction in relation to tensile reinforcement and the exposure conditions in the salt-fog chamber. The cracking maps, corrosion maps, chloride profiles, and cross-sectional loss of one group of two beams cast in 2010 were studied and their calculated corrosion rates were compared to that of beams cast in 1984 in order to investigate the factors influencing the natural corrosion process. Experimental results show that, after rapid initiation of corrosion at the crack tip, the corrosion process practically halted and the time elapsing before corrosion resumed depended on the exposure conditions and cover depth.

  5. 煤矿低压系统动态无功补偿优化%Optimization of Reactive-load Compensation of Low Voltage System in Coal Mine

    Institute of Scientific and Technical Information of China (English)

    刘天野

    2014-01-01

    针对煤矿低压供电系统中功率因数低、电能质量不稳等问题,对煤矿低压系统无功功率补偿应用情况进行了研究。在分析了无功功率补偿方式和原理的基础上,提出了煤矿低压系统无功补偿优化算法,使线损在矿区低压系统无功平衡条件下达到最小。%Aiming at low power factor and instable electric energy quality of low voltage power supply system in coal mine ,this paper studied reactive-load compensation in low voltage system .On the basis of analysis of the reactive-load compensation principle and method ,the algorithm for optimization of reactive-load compensation in low voltage system was proposed ,achieving minimum line loss in the condition of balanced reactive component .

  6. Beam induced heat loads on the beam-screens of the twin-bore magnets in the IRs of the HL-LHC

    CERN Document Server

    Iadarola, Giovanni; Rumolo, Giovanni

    2016-01-01

    The expected heat load induced on the beam screens has been evaluated for all the twin-bore magnets in the Insertion Regions (IRs) of the HL-LHC. The contribution from the impedance of the beam screen has been evaluated taking into account the presence of a longitudinal weld in the beam screen and the impact of the temperature and of the magnetic field on the resistivity of the surface. The contribution coming from electron cloud effects has been evaluated for different values of the Secondary Electron Yield of the surface based PyECLOUD build-up simulations.

  7. SU-E-T-61: A Practical Process for Fabricating Passive Scatter Proton Beam Modulation Compensation Filters Using 3D Printing

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, T; Drzymala, R [Washington University School of Medicine, St. Louis, MO (United States)

    2015-06-15

    Purpose: The purpose of this project was to devise a practical fabrication process for passive scatter proton beam compensation filters (CF) that is competitive in time, cost and effort using 3D printing. Methods: DICOM compensator filter files for a proton beam were generated by our Eclipse (Varian, Inc.) treatment planning system. The compensator thickness specifications were extracted with in-house software written in Matlab (MathWorks, Inc.) code and written to a text file which could be read by the Rhinoceros 5, computer-aided design (CAD) package (Robert McNeel and Associates), which subsequently generated a smoothed model in a STereoLithographic also known as a Standard Tesselation Language file (STL). The model in the STL file was subsequently refined using Netfabb software and then converted to printing instructions using Cura. version 15.02.1. for our 3D printer. The Airwolf3D, model HD2x, fused filament fabrication (FFF) 3D printer (Airwolf3D.com) was used for our fabrication system with a print speed of 150mm per second. It can print in over 22 different plastic filament materials in a build volume of 11” x 8” x 12”. We choose ABS plastic to print the 3D model of the imprint for our CFs. Results: Prints of the CF could be performed at a print speed of 70mm per second. The time to print the 3D topology for the CF for the 14 cm diameter snout of our Mevion 250 proton accelerator was less than 3 hours. The printed model is intended to subsequently be used as a mold to imprint a molten wax cylindrical to form the compensation after cooling. The whole process should be performed for a typical 3 beam treatment plan within a day. Conclusion: Use of 3D printing is practical and can be used to print a 3D model of a CF within a few hours.

  8. A wide load range, multi-mode synchronous buck DC—DC converter with a dynamic mode controller and adaptive slope compensation

    Science.gov (United States)

    Chunhong, Zhang; Haigang, Yang; Shi, Richard

    2013-06-01

    A synchronous buck DC—DC converter with an adaptive multi-mode controller is proposed. In order to achieve high efficiency over its entire load range, pulse-width modulation (PWM), pulse-skip modulation (PSM) and pulse-frequency modulation (PFM) modes were integrated in the proposed DC—DC converter. With a highly accurate current sensor and a dynamic mode controller on chip, the converter can dynamically change among PWM, PSM and PFM control according to the load requirements. In addition, to avoid power device damage caused by inrush current at the start up state, a soft-start circuit is presented to suppress the inrush current. Furthermore, an adaptive slope compensation (SC) technique is proposed to stabilize the current programmed PWM controller for duty cycle passes over 50%, and improve the degraded load capability due to traditional slope compensation. The buck converter chip was simulated and manufactured under a 0.35 μm standard CMOS process. Experimental results show that the chip can achieve 79% to 91% efficiency over the load range of 0.1 to 1000 mA

  9. A wide load range, multi-mode synchronous buck DC-DC converter with a dynamic mode controller and adaptive slope compensation

    Institute of Scientific and Technical Information of China (English)

    Zhang Chunhong; Yang Haigang; Richard Shi

    2013-01-01

    A synchronous buck DC-DC converter with an adaptive multi-mode controller is proposed.In order to achieve high efficiency over its entire load range,pulse-width modulation (PWM),pulse-skip modulation (PSM)and pulse-frequency modulation (PFM) modes were integrated in the proposed DC-DC converter.With a highly accurate current sensor and a dynamic mode controller on chip,the converter can dynamically change among PWM,PSM and PFM control according to the load requirements.In addition,to avoid power device damage caused by inrush current at the start up state,a soft-start circuit is presented to suppress the inrush current.Furthermore,an adaptive slope compensation (SC) technique is proposed to stabilize the current programmed PWM controller for duty cycle passes over 50%,and improve the degraded load capability due to traditional slope compensation.The buck converter chip was simulated and manufactured under a 0.35μm standard CMOS process.Experimental results show that the chip can achieve 79% to 91% efficiency over the load range of 0.1 to 1000 mA.

  10. 舵机负载模拟器惯量失配加载补偿方法%Missile Actuator Load Simulator Inertia Mismatch Compensation Methods

    Institute of Scientific and Technical Information of China (English)

    陶渝辉; 王战

    2012-01-01

    The compensation methods are discussed when load simulator inertia is greater than missile control surface inertia. Errors of missile actuator torque and deflection angle exist in simulation using compensation. The approaches are presented to improve simulation according to different errors. Analysis results show that the compensation method is useable and valuable to many missile actuator load simulations.%针对舵机负载力矩模拟器输出等效惯量大于被加载舵机舵面惯量的舵机加载试验情况,研究了其力矩加载补偿方法,分析了其力矩加载误差,提出了针对不同误差源的提高仿真精度的技术途径.分析结果表明,此力矩加载补偿方法现实可行,提高了试验资源的利用率,具有较好的经济效益和现实意义.

  11. Field Testing and Load Rating Report for Bridge No. 4, Hybrid Composite Beam Span, at Fort Knox, Kentucky

    Science.gov (United States)

    2016-09-01

    metal guardrail as the military vehicles crossed the structure ; especially during the first tests run near the structure’s edges (Test Paths Y1 & Y3...were the first time these details were heavily loaded. In general, this type of behavior is common for newer structures and does not affect the...Composite Beams for Bridges for Project F12-AR15, “Corrosion-Resistant Hybrid Composite Bridge Beams for Structural Applications” Monitored by

  12. Shock loading characteristics of Zr and Ti metals using dual beam velocimeter

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, A. K., E-mail: a-saxena@barc.gov.in; Kaushik, T. C.; Gupta, Satish C. [Applied Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2015-08-21

    The characteristics of titanium and zirconium metal foils under shock loading have been studied up to 16 GPa and 12 GPa pressure, respectively, using portable electric gun setup as projectile launcher. In these experiments, the capabilities of a single Fabry-Perot velocimeter have been enhanced by implementing it in dual beam mode to record the two velocity profiles on a single streak camera. The measured equation of state data for both the metals have been found to be well in agreement with the reported Hugoniot, within experimental accuracies. A phase transition from α to ω phase has been detected near to 11.4 GPa for titanium and 8.2 GPa for zirconium in the rising part of target-glass interface velocity profile.

  13. Comparison of the Performance of Chilled Beam with Swirl Jet and Diffuse Ceiling Air Supply: Impact of Heat Load Distribution

    DEFF Research Database (Denmark)

    Bertheussen, Bård; Mustakallio, Panu; Kosonen, Risto

    2013-01-01

    The impact of heat load strength and positioning on the indoor environment generated by diffuse ceiling air supply and chilled beam with radial swirl jet was studied and compared. An office room with two persons and a meeting room with six persons were simulated in a test room (4.5 x 3.95 x 3.5 m3...... (ventilation effectiveness of 0.4) and the air flow rate had to be above minimum to safeguard the indoor air quality. The radial swirl jet of chilled beam also was not capable of creating complete mixing at high and concentrated heat load (ventilation effectiveness of 0.7)....

  14. Instability of Annular Beam with Finite Thickness in Dielectric-Loaded Cylindrical Waveguide

    OpenAIRE

    Tamura, Shusuke; Yamakawa, Mitsuhisa; Takashima, Yusuke; Ogura, Kazuo

    2008-01-01

    The cherenkov and slow cyclotron instabilities driven by an axially injected electron beam in a cylindrical waveguide are studied using a new version of the self-consistent linear theory considering three-dimensional beam perturbations. There are three kinds of models for beam instability analysis, which are based on a cylindrical solid beam, an infinitesimally thin annular beam, and a finitely thick annular beam. Among these models, the beam shape properly representing the often used actual ...

  15. Vibration reduction in beam bridge under moving loads using nonlinear smooth and discontinuous oscillator

    Directory of Open Access Journals (Sweden)

    Ruilan Tian

    2016-06-01

    Full Text Available The coupled system of smooth and discontinuous absorber and beam bridge under moving loads is constructed in order to detect the effectiveness of smooth and discontinuous absorber. It is worth pointing out that the coupled system contains an irrational restoring force which is a barrier for conventional nonlinear techniques. Hence, the harmonic balance method and Fourier expansion are used to obtain the approximate solutions of the system. The first and the second kind of generalized complete elliptic integrals are introduced. Furthermore, using power flow approach, the performance of smooth and discontinuous absorber in vibration reduction is estimated through the input energy, the dissipated energy, and the damping efficiency. It is interesting that only depending on the value of the smoothness parameter, the efficiency parameter of vibration reduction is optimized. Therefore, smooth and discontinuous absorber can adapt itself to effectively reducing the amplitude of the vibration of the beam bridge, which provides an insight to the understanding of the applications of smooth and discontinuous oscillator in engineering and power flow characteristics in nonlinear system.

  16. 液压振动台负载流量补偿方法的研究%Study on load-flow compensation of hydraulic vibration table

    Institute of Scientific and Technical Information of China (English)

    刘博; 侯京锋; 窦雪川; 张静; 郝岩研; 王家乐; 王有杰

    2014-01-01

    通过将负载变化折算为相应控制指令,并与期望指令相叠加后,作为最终的控制指令输出给伺服阀,构造负载流量与期望控制指令之间的比例关系,实现了液压振动台抑制负载干扰对流量波动的影响,提高了液压振动台运动控制精度。经过流量补偿后的液压振动台在负载变化时可以实现对输入指令较好的跟踪,可对机械振动或冲击环境进行更好的模拟。%By superposing the control command converted from the varying load and the expected control command as the last control command, the linear dependency between the load-flow and the expected control command is constructed. The method could achieve the suppression of load-flow fluctuation influenced by load variation, and improve the control precision of the table. The hydraulic vibration table could track the expected command with load varying well by the load-flow compensation method, and simulate the vibration environment and the shock environment better.

  17. Analysis of a Beam Made of Physical Nonlinear Material on Nonlinear Elastic Foundation under a Moving Concentrated Load

    Directory of Open Access Journals (Sweden)

    E. Mardani

    2008-01-01

    Full Text Available A prismatic beam made of a behaviorally nonlinear material was analyzed under a concentrated load moving with a known velocity on a nonlinear elastic foundation with a reaction the vibration equation of motion was derived using Hamilton principle and Euler Lagrange equation. The amplitude of vibration, circular frequency, bending moment, stress and deflection of the beam can be calculated by the presented solution. Considering the response of the beam, in the sense of its resonance, it was found that there is no critical velocity when the behavior of the beam and foundation material is assumed to be physically nonlinear and there are finite values for the deflection, stress and bending moment of the beam when

  18. Measurement of Deflection in Concrete Beams During Fatigue Loading Test Using the Microsoft Kinect 2.0

    Science.gov (United States)

    Lahamy, Herve; Lichti, Derek D.; Steward, Jeremy; El-Badry, Mamdouh; Moravvej, Mohammad

    2016-03-01

    This study focuses on 3 Hz fatigue load testing of a reinforced concrete beam in laboratory conditions. Three-dimensional (3D) image time series of the beam's top surface were captured with the Microsoft time-of-flight Kinect 2.0 sensor. To estimate the beam deflection, the imagery was first segmented to extract the top surface of the beam. The centre line was then modeled using third-order B-splines. The deflection of the beam as a function of time was estimated from the modeled centre line and, following past practice, also at several witness plates attached to the side of the beam. Subsequent correlation of the peak displacement with the applied loading cycles permitted estimation of fatigue in the beam. The accuracy of the deflections was evaluated by comparison with the measurements obtained using a Keyence LK-G407 laser displacement sensors. The results indicate that the deflections can be recovered with sub-millimetre accuracy using the centreline profile modelling method.

  19. Multiple linear regression models for shear strength prediction and design of simplysupported deep beams subjected to symmetrical point loads

    Directory of Open Access Journals (Sweden)

    Panatchai Chetchotisak

    2015-09-01

    Full Text Available Because of nonlinear strain distributions caused either by abrupt changes in geometry or in loading in deep beam, the approach for conventional beams is not applicable. Consequently, strut-and-tie model (STM has been applied as the most rational and simple method for strength prediction and design of reinforced concrete deep beams. A deep beam is idealized by the STM as a truss-like structure consisting of diagonal concrete struts and tension ties. There have been numerous works proposing the STMs for deep beams. However, uncertainty and complexity in shear strength computations of deep beams can be found in some STMs. Therefore, improvement of methods for predicting the shear strengths of deep beams are still needed. By means of a large experimental database of 406 deep beam test results covering a wide range of influencing parameters, several shapes and geometry of STM and six state-of-the-art formulation of the efficiency factors found in the design codes and literature, the new STMs for predicting the shear strength of simply supported reinforced concrete deep beams using multiple linear regression analysis is proposed in this paper. Furthermore, the regression diagnostics and the validation process are included in this study. Finally, two numerical examples are also provided for illustration.

  20. A NEW HYSTERESIS COMPENSATION METHOD FOR LOAD CELLS%称重传感器的一种新的滞后补偿方法

    Institute of Scientific and Technical Information of China (English)

    朱子健; 陈仁文

    2002-01-01

    A new hysteresis compensation method is presented. After analyzing the characteristics of strain-gage based load cells under loading & unloading conditions, mathematical models are established. A solution to compensate the hysteresis of the load cell by software in the terminal is brought forward and is verified by the experiments. It is shown that the method is reliable and can effectively reduce the hysteresis.%通过对电阻应变式称重传感器在各种加载卸载情况下的滞后特性的分析,建立了其相应的数学模型,并初步探讨了一种可以通过程序在仪表中对传感器的重要指标-滞后进行补偿从而提高整个传感器的精度的方法.最后,对以上方法进行了验证性试验,证明了补偿方法的可行性.

  1. Motion compensator for holographic motion picture camera

    Science.gov (United States)

    Kurtz, R. L.

    1973-01-01

    When reference beam strikes target it undergoes Doppler shift dependent upon target velocity. To compensate, object beam is first reflected from rotating cylinder that revolves in direction opposite to target but at same speed. When beam strikes target it is returned to original frequency and is in phase with reference beam. Alternatively this motion compensator may act on reference beam.

  2. Analytical Solution for the Sound Radiation Field of a Viscoelastically Supported Beam Traversed by a Moving Load

    Directory of Open Access Journals (Sweden)

    Rezgar Shakeri

    2014-01-01

    Full Text Available Sound radiation from a beam resting on a viscoelastic foundation is analytically studied when it is subjected to a moving load. The topic could cover a range of applications such as submerged floating tunnels, buried pipelines, and railway tracks. Galerkin’s method is employed to obtain the transverse vibration of the beam. Based on the Rayleigh integral approach, acoustic pressure distribution around the beam is obtained in the time domain. In the second part of this paper, corresponding displacement and acoustic pressure are obtained by the use of the Rayleigh-Ritz approach in conjunction with the Laplace transform method and by the use of the Fourier transform, respectively. Durbin’s numerical Laplace transform inversion scheme is eventually employed to obtain dynamic responses. A parametric study is then carried out and influences of the design parameters as well as the loading conditions on the acoustic pressure field are investigated.

  3. High-performance control of a three-phase voltage-source converter including feedforward compensation of the estimated load current

    Energy Technology Data Exchange (ETDEWEB)

    Leon, Andres E.; Solsona, Jorge A.; Busada, Claudio; Chiacchiarini, Hector [Instituto de Investigaciones en Ingenieria Electrica (IIIE) UNS-CONICET, Universidad Nacional del Sur, Av. Alem 1253, Bahia Blanca 8000 (Argentina); Valla, Maria Ines [Laboratorio de Electronica Industrial, Control e Instrumentacion (LEICI) and CONICET, Facultad de Ingenieria, Universidad Nacional de La Plata, La Plata 1900 (Argentina)

    2009-08-15

    In this paper a new control strategy for voltage-source converters (VSC) is introduced. The proposed strategy consists of a nonlinear feedback controller based on feedback linearization plus a feedforward compensation of the estimated load current. In our proposal an energy function and the direct-axis current are considered as outputs, in order to avoid the internal dynamics. In this way, a full linearization is obtained via nonlinear transformation and feedback. An estimate of the load current is feedforwarded to improve the performance of the whole system and to diminish the capacitor size. This estimation allows to obtain a more rugged and cheaper implementation. The estimate is calculated by using a nonlinear reduced-order observer. The proposal is validated through different tests. These tests include performance in presence of switching frequency, measurement filters delays, parameters uncertainties and disturbances in the input voltage. (author)

  4. Deflection analysis of reinforced concrete beams strengthened with carbon fibre reinforced polymer under long-term load action

    Institute of Scientific and Technical Information of China (English)

    Mykolas DAUGEVI(C)IUS; Juozas VALIVONIS; Gediminas MAR(C)IUKAITIS

    2012-01-01

    This paper presents the results of an experimental research on reinforced concrete beams strengthened with an external carbon fibre reinforced polymer (CFRP) layer under long-term load action that lasted for 330 d.We describe the characteristics of deflection development of the beams strengthened with different additional anchorages of the external carbon fibre composite layer during the period of interest.The conducted experiments showed that the additional anchorage influences the slip of the extemal layer with respect to the strengthened element.Thus,concrete and carbon fibre composite interface stiffness decreases with a long-term load action.Therefore,the proposed method of analysis based on the built-up-bars theory can be used to estimate concrete and carbon fibre composite interface stiffness in the case of long-term load.

  5. Timoshenko beam-column with generalized end conditions on elastic foundation: Dynamic-stiffness matrix and load vector

    Science.gov (United States)

    Arboleda-Monsalve, Luis G.; Zapata-Medina, David G.; Aristizabal-Ochoa, J. Darío

    2008-03-01

    The dynamic-stiffness matrix and load vector of a Timoshenko beam-column resting on a two-parameter elastic foundation with generalized end conditions are presented. The proposed model includes the frequency effects on the stiffness matrix and load vector as well as the coupling effects of: (1) bending and shear deformations along the member; (2) translational and rotational lumped masses at both ends; (3) translational and rotational masses uniformly distributed along its span; (3) axial load (tension or compression) applied at both ends; and (4) shear forces along the span induced by the applied axial load as the beam deforms according to the "modified shear equation" proposed by Timoshenko. The dynamic analyses of framed structures can be performed by including the effects of the imposed frequency ( ω>0) on the dynamic-stiffness matrix and load vector while the static and stability analyses can be carried out by making the frequency ω=0. The proposed model and corresponding dynamic-stiffness matrix and load vector represent a general solution capable to solve, just by using a single segment per element, the static, dynamic and stability analyses of any elastic framed structure made of prismatic beam-columns with semi-rigid connections resting on two-parameter elastic foundations. Analytical results indicate that the elastic behavior of framed structures made of beam-columns is frequency dependent and highly sensitive to the coupling effects just mentioned. Three comprehensive examples are presented to show the capacities and validity of the proposed method and the obtained results are compared with the finite element method and other analytical approaches.

  6. Static Analysis of Functionally Graded Piezoelectric Beams under Thermo-Electro-Mechanical Loads

    Directory of Open Access Journals (Sweden)

    Amin Komeili

    2011-01-01

    Full Text Available This paper presents the analysis of static bending of beams made of functionally graded piezoelectric materials (FGPMs under a combined thermo-electro-mechanical load. The Euler Bernoulli theory (EBT, first-order shear deformation theory (FSDT and third-order shear deformation theory (TSDT were employed to compare the accuracy and the reliability of each theory in applications. The material properties vary continuously through the thickness direction. The material compositions were selected from the PZT family. The governing equations were derived from Hamilton's principle and solved using the finite element method and Fourier series method. Cubic Hermit interpolation shape function was used for estimating the transverse deflection, and the linear interpolation function was used for the axial displacement and the shear rotation as well. Fourier series expansion, based on the boundary conditions, were employed to solve the governing equations analytically. The accuracy of the method was validated by comparing the results with the previous studies. Finite element results were compared with the analytical results presented in this paper. A comprehensive parametric study is conducted to show the influence of the voltage, shear deformation, material composition, end supports, and the slenderness ratio on the thermo-electro-mechanical characteristic.

  7. Forced Vibration of a Timoshenko Beam Subjected to Stationary and Moving Loads Using the Modal Analysis Method

    Directory of Open Access Journals (Sweden)

    Taehyun Kim

    2017-01-01

    Full Text Available The modal analysis method (MAM is very useful for obtaining the dynamic responses of a structure in analytical closed forms. In order to use the MAM, accurate information is needed on the natural frequencies, mode shapes, and orthogonality of the mode shapes a priori. A thorough literature survey reveals that the necessary information reported in the existing literature is sometimes very limited or incomplete, even for simple beam models such as Timoshenko beams. Thus, we present complete information on the natural frequencies, three types of mode shapes, and the orthogonality of the mode shapes for simply supported Timoshenko beams. Based on this information, we use the MAM to derive the forced vibration responses of a simply supported Timoshenko beam subjected to arbitrary initial conditions and to stationary or moving loads (a point transverse force and a point bending moment in analytical closed form. We then conduct numerical studies to investigate the effects of each type of mode shape on the long-term dynamic responses (vibrations, the short-term dynamic responses (waves, and the deformed shapes of an example Timoshenko beam subjected to stationary or moving point loads.

  8. Free and Forced Vibrations of an Axially-Loaded Timoshenko Multi-Span Beam Carrying a Number of Various Concentrated Elements

    OpenAIRE

    Yusuf Yesilce

    2012-01-01

    In the existing reports regarding free and forced vibrations of the beams, most of them studied a uniform beam carrying various concentrated elements using Bernoulli-Euler Beam Theory (BET) but without axial force. The purpose of this paper is to utilize the numerical assembly technique to determine the exact frequency-response amplitudes of the axially-loaded Timoshenko multi-span beam carrying a number of various concentrated elements (including point masses, rotary inertias, linear springs...

  9. 考虑地方电厂的可中断负荷补偿方法%Compensation methods for interruptible load in the presence of local power generation

    Institute of Scientific and Technical Information of China (English)

    糜晓波; 王文华; 唐永伟; 张少华

    2012-01-01

    Optimization problem for dispatch between local power generation and interruptible load(IL) resources when electricity shortage happens is addressed.Emphasis is given to the issue of how to determine the economic compensation in the IL programs,with which a consistent choice for the load interruption by power supply-side and demand-side can be realized and at the same time the optimal social welfare can be achieved.For this purpose,two compensation methods,namely the linear compensation and the nonlinear compensation,are developed.Numerical simulation shows that as compared with the linear compensation,the nonlinear compensation leads to a lower compensation price,which means that using the nonlinear compensation method,load management with optimal social welfare can be achieved by a relatively small amount of economic compensation.%针对供电紧张时地方电厂和可中断负荷资源之间的优化调度问题,重点研究了如何确定可中断负荷的经济补偿,使得供电侧和用户侧对于负荷中断量的选择能协调一致,并达到社会效益最优。设计了两种负荷中断补偿方法,即线性补偿和非线性补偿,并通过算例分析表明,与线性补偿相比,非线性补偿具有较低的单位补偿价格,即通过较小的经济补偿就能实现社会效益最优的负荷管理策略。

  10. A more economical compensation method for unbalanced load%不平衡负载的一种更加经济的补偿方法

    Institute of Scientific and Technical Information of China (English)

    傅军栋; 喻勇; 黄来福

    2015-01-01

    For low-voltage distribution network unbalanced load loss reduction, we think of the capacitance compensation, which can improve the power factor of power grid and reduce the loss of power transformers and transmission lines, as well as improve the efficiency of power supply improvement and environment in the power supply system. Traditional methods simply calculate the admittance compensation value required by the load, then configure the appropriate capacitor;a relatively new kind of admittance calculation method is the balance component method. This paper puts forward a "Line Adjustment Act" drop loss compensation method to perform three phase load line regulation, which only adjusts the access phase of users’ meter box. A commutation strategy based on intelligent optimization algorithm is proposed, which does not require additional investment, and through a numerical example, the validity and effectiveness of this method are verified. Therefore, the"Line Adjustment Act"is a more simple and more economical method of reducing loss.%针对低压配电网不平衡负载降损的问题,会联想到电容补偿器,其在供电系统中起到提高电网的功率因数与降低供电变压器及输送线路的损耗,提高供电效率以及改善供电环境的作用。传统方法只需计算出负载所需要补偿的导纳值,然后配置相应的电容器,比较新的一种导纳值计算方法如平衡分量法。提出一种“线路调整法”的降损补偿方法,进行负荷三相平衡线路调整,仅需对用户集表箱的接入相做调整。提出一种基于优化算法的智能换相策略,不需要增加额外投资,通过算例分析验证了此方法的正确性和有效性。因此,“线路调整法”是一种更简单、更经济的降损方法。

  11. Characteristic values of the lumbar load of manual patient handling for the application in workers' compensation procedures

    Directory of Open Access Journals (Sweden)

    Wortmann Norbert

    2011-05-01

    Full Text Available Abstract Background The human spine is often exposed to mechanical load in vocational activities especially in combination with lifting, carrying and positioning of heavy objects. This also applies in particular to nursing activities with manual patient handling. In the present study a detailed investigation on the load of the lumbar spine during manual patient handling was performed. Methods For a total of 13 presumably endangering activities with transferring a patient, the body movements performed by healthcare workers were recorded and the exerted action forces were determined with regard to magnitude, direction and lateral distribution in the time course with a "measuring bed", a "measuring chair" and a "measuring floor". By the application of biomechanical model calculations the load on the lowest intervertebral disc of the lumbar spine (L5-S1 was determined considering the posture and action force data for every manual patient handling. Results The results of the investigations reveal the occurrence of high lumbar load during manual patient handling activities, especially in those cases, where awkward postures of the healthcare worker are combined with high action forces caused by the patient's mass. These findings were compared to suitable issues of corresponding investigations provided in the literature. Furthermore measurement-based characteristic values of lumbar load were derived for the use in statement procedures concerning the disease no. 2108 of the German list of occupational diseases. Conclusions To protect healthcare workers from mechanical overload and the risk of developing a disc-related disease, prevention measures should be compiled. Such measures could include the application of "back-fairer" nursing techniques and the use of "technical" and" small aids" to reduce the lumbar load during manual patient handling. Further studies, concerning these aspects, are necessary.

  12. Monitoring and Compensation of Large-Size Flat-Top Laser Beam%大尺寸平顶激光光束的监测补偿

    Institute of Scientific and Technical Information of China (English)

    赵天卓; 樊仲维; 余锦; 麻云凤; 刘洋; 张雪; 闫莹

    2011-01-01

    介绍了为一个平顶激光光束放大器所搭建的监测和补偿系统.该放大器采用多级放大结构,能够输出单脉冲能量5 J,光斑尺寸50 min×50 mm的平顶激光光束.放大器内部的液晶光阀可以对输出光斑的能量分布进行有效的调制.监控系统与放大器中的空间滤波器相结合,通过傅里叶像传递的原理,将液晶光阀上的能量分布成像到监测CCD上.补偿系统通过将放大器输出光斑反馈到液晶光阀上,有效的提高了输出激光光束的质量.实验结果表明,整形后的光斑内部能量分布更加均匀,放大器输出的平顶激光光束近场调制度为1.64,软化因子为0.053.所设计的监测和补偿系统较好的实现了对光束质量的控制和改善.%A monitoring and compensation system which is built for an amplifier that can generate flat-top laser beam is described. The amplifier uses a multi-level amplification structure. It can output 5 J energy of a single pulse, and the spot size of the flat-top laser beam is 50 mm × 50 mm. The liquid-crystal valve in the amplifier can modulate energy distribution of the output spot effectively. The monitoring system is combined with the spatial filter in the amplifier, and by the theory of Fourier-image transfer, it can image energy distribution of the liquid-crystal valve on the monitoring CCD. The compensation system effectively improves the quality of the output laser beam by feeding back the output spot of the amplifier on the liquid-crystal valve. Experimental result shows that energy distribution of the shaped beam is more uniform, and the near-field modulation of the flat-top laser beam generated by the amplifier is 1.64, the softening factor is 0. 053. The beam-quality control and improvement are well realized by the monitoring and compensation structure.

  13. Mixed-frame and stationary-frame repetitive control schemes for compensating typical load and grid harmonics

    DEFF Research Database (Denmark)

    Loh, P.; Tang, Y.; Blaabjerg, Frede;

    2011-01-01

    In this study, repetitive current controllers operating in either the mixed or stationary frame are proposed for high-precision reference tracking and disturbance rejection of power converters. Both controllers use a proportional-resonant regulator in the stationary frame for regulating...... the positive- and negative-sequence fundamental currents, which are known to directly influence the flow of active and reactive power in most energy conversion systems. Moreover, for the tracking or compensation of harmonics, the controllers include a repetitive control path in either the synchronous...... or stationary frame, whose inherent feedback and feedforward structure is proven to resemble a bank of resonant filters in either reference frames. Unlike other existing controllers, the proposed repetitive controllers function by introducing multiple resonant peaks at only those harmonic frequencies typically...

  14. Prediction and compensation of magnetic beam deflection in MR-integrated proton therapy: a method optimized regarding accuracy, versatility and speed

    Science.gov (United States)

    Schellhammer, Sonja M.; Hoffmann, Aswin L.

    2017-02-01

    The integration of magnetic resonance imaging (MRI) and proton therapy for on-line image-guidance is expected to reduce dose delivery uncertainties during treatment. Yet, the proton beam experiences a Lorentz force induced deflection inside the magnetic field of the MRI scanner, and several methods have been proposed to quantify this effect. We analyze their structural differences and compare results of both analytical and Monte Carlo models. We find that existing analytical models are limited in accuracy and applicability due to critical approximations, especially including the assumption of a uniform magnetic field. As Monte Carlo simulations are too time-consuming for routine treatment planning and on-line plan adaption, we introduce a new method to quantify and correct for the beam deflection, which is optimized regarding accuracy, versatility and speed. We use it to predict the trajectory of a mono-energetic proton beam of energy E 0 traversing a water phantom behind an air gap within an omnipresent uniform transverse magnetic flux density B 0. The magnetic field induced dislocation of the Bragg peak is calculated as function of E 0 and B 0 and compared to results obtained with existing analytical and Monte Carlo methods. The deviation from the Bragg peak position predicted by Monte Carlo simulations is smaller for the new model than for the analytical models by up to 2 cm. The model is faster than Monte Carlo methods, less assumptive than the analytical models and applicable to realistic magnetic fields. To compensate for the predicted Bragg peak dislocation, a numerical optimization strategy is introduced and evaluated. It includes an adjustment of both the proton beam entrance angle and energy of up to 25° and 5 MeV, depending on E 0 and B 0. This strategy is shown to effectively reposition the Bragg peak to its intended location in the presence of a magnetic field.

  15. Prediction and compensation of magnetic beam deflection in MR-integrated proton therapy: a method optimized regarding accuracy, versatility and speed.

    Science.gov (United States)

    Schellhammer, Sonja M; Hoffmann, Aswin L

    2017-02-21

    The integration of magnetic resonance imaging (MRI) and proton therapy for on-line image-guidance is expected to reduce dose delivery uncertainties during treatment. Yet, the proton beam experiences a Lorentz force induced deflection inside the magnetic field of the MRI scanner, and several methods have been proposed to quantify this effect. We analyze their structural differences and compare results of both analytical and Monte Carlo models. We find that existing analytical models are limited in accuracy and applicability due to critical approximations, especially including the assumption of a uniform magnetic field. As Monte Carlo simulations are too time-consuming for routine treatment planning and on-line plan adaption, we introduce a new method to quantify and correct for the beam deflection, which is optimized regarding accuracy, versatility and speed. We use it to predict the trajectory of a mono-energetic proton beam of energy E 0 traversing a water phantom behind an air gap within an omnipresent uniform transverse magnetic flux density B 0. The magnetic field induced dislocation of the Bragg peak is calculated as function of E 0 and B 0 and compared to results obtained with existing analytical and Monte Carlo methods. The deviation from the Bragg peak position predicted by Monte Carlo simulations is smaller for the new model than for the analytical models by up to 2 cm. The model is faster than Monte Carlo methods, less assumptive than the analytical models and applicable to realistic magnetic fields. To compensate for the predicted Bragg peak dislocation, a numerical optimization strategy is introduced and evaluated. It includes an adjustment of both the proton beam entrance angle and energy of up to 25° and 5 MeV, depending on E 0 and B 0. This strategy is shown to effectively reposition the Bragg peak to its intended location in the presence of a magnetic field.

  16. Image-based compensation for involuntary motion in weight-bearing C-arm cone-beam CT scanning of knees

    Science.gov (United States)

    Unberath, Mathias; Choi, Jang-Hwan; Berger, Martin; Maier, Andreas; Fahrig, Rebecca

    2015-03-01

    We previously introduced four fiducial marker-based strategies to compensate for involuntary knee-joint motion during weight-bearing C-arm CT scanning of the lower body. 2D methods showed significant reduction of motion- related artifacts, but 3D methods worked best. However, previous methods led to increased examination times and patient discomfort caused by the marker attachment process. Moreover, sub-optimal marker placement may lead to decreased marker detectability and therefore unstable motion estimates. In order to reduce overall patient discomfort, we developed a new image-based 2D projection shifting method. A C-arm cone-beam CT system was used to acquire projection images of five healthy volunteers at various flexion angles. Projection matrices for the horizontal scanning trajectory were calibrated using the Siemens standard PDS-2 phantom. The initial reconstruction was forward projected using maximum-intensity projections (MIP), yielding an estimate of a static scan. This estimate was then used to obtain the 2D projection shifts via registration. For the scan with the most motion, the proposed method reproduced the marker-based results with a mean error of 2.90 mm +/- 1.43 mm (compared to a mean error of 4.10 mm +/- 3.03 mm in the uncorrected case). Bone contour surrounding modeling clay layer was improved. The proposed method is a first step towards automatic image-based, marker-free motion-compensation.

  17. Experimental Study On Lateral Load Capacity of Bamboo RC Beam Column Joints Strengthened By Bamboo Mechanical Anchors

    Directory of Open Access Journals (Sweden)

    Sri Umniati B.

    2017-01-01

    Full Text Available In this paper, the prospective of bamboos which available abundantly especially in Indonesia as rebars and mechanical anchors are studied. And also the endurance of the bamboos mechanical anchors to withstand cyclic loading were observed. Nine classes of bamboos bar were evaluated: consist of 3 different anchors (0, 4 and 8 anchors and 3 different compressive strength (19.19 MPa, 29.61 MPa and 37.96 MPa means 3 × 3 parameters. The results show that the lateral load capacity increased significantly with the present of bamboo anchors specimens: 26.04 % for 4 anchors specimens (C2 and 25 % for the 8 anchors specimens (C3 compared to zero anchor specimens (C1. On the other hand, the compressive strength of concrete have no significant effects to the lateral load capacity. Overall it can be concluded that, bamboo can be used as mechanical anchorage to strengthen beam column joint.

  18. A Novel Friction Compensation Method Using Positive Torque Load%使用主动阻力矩的摩擦补偿新方法

    Institute of Scientific and Technical Information of China (English)

    庄文许; 杨必武; 马大为; 孟庆爱; 张秀维

    2012-01-01

    Aiming at phenomena of Vibrations and stick-slip motions caused by friction in the rotating servosystem, a novel friction compensation method using positive torque load was proposed. The principle of which was, while the servosystem operated at low speed, by giving an additional torque load to compensate the system and improving gain factor of the servosystem controller, the sensitivity was reduced between the regulated output and friction torque load of the servo system. By using sensitivity equations and the stability law, this method was proved to be efficient. Based on the method, a compensation system, which used a magnetorheological detent as a core was designed. And it was used in a typical position control system, and a simulation model was established. The simulation results show that the peak value of the tracking error undulation under a given disturbance is reduced from 0.45° to 0. 025° by increasing the value of the positive torque from zero to as big as eight times of the given disturbance. The method was high real-time, and the disadvantage of system vibrating when using a high gain controller was conquered. Both theoretical analysis and simulation results demonstrate that the phenomena of friction stick-slip motions and vibrations are rejected significantly by the compensation system.%针对旋转伺服系统中摩擦造成低速爬行和振荡现象,提出使用主动阻力矩进行摩擦补偿的方法,其原理是当伺服系统低速运行时,通过补偿系统主动增加负载阻力矩,并提高伺服系统控制器增益系数来降低系统输出调节量对摩擦力矩的灵敏度,应用灵敏度方程和稳定性理论证明了该方法的有效性.基于该方法设计了以磁流变制动器为核心的补偿系统,并将其应用于典型位置控制系统,建立仿真模型,仿真结果显示,在给定干扰力矩作用下,从零增加主动阻力矩至与干扰力矩数值比达到8时,跟踪误差波动幅值从0.45°降低至0

  19. Large deflection analysis of cantilever beam under end point and distributed load

    DEFF Research Database (Denmark)

    Kimiaeifar, Amin; Tolou, N; Barari, Amin;

    2014-01-01

    Although the deflection of beams has been studied for decades, the solutions were either linearized (i.e. small deflection) or based on elliptic integrals or functions (large deflection). The latter one includes the geometric nonlinearity but calculation of the deflection along the beam length re...

  20. Numerical Simulation of Output Response of PVDF Sensor Attached on a Cantilever Beam Subjected to Impact Loading.

    Science.gov (United States)

    Dung, Cao Vu; Sasaki, Eiichi

    2016-04-27

    Polyvinylidene Flouride (PVDF) is a film-type polymer that has been used as sensors and actuators in various applications due to its mechanical toughness, flexibility, and low density. A PVDF sensor typically covers an area of the host structure over which mechanical stress/strain is averaged and converted to electrical energy. This study investigates the fundamental "stress-averaging" mechanism for dynamic strain sensing in the in-plane mode. A numerical simulation was conducted to simulate the "stress-averaging" mechanism of a PVDF sensor attached on a cantilever beam subjected to an impact loading, taking into account the contribution of piezoelectricity, the cantilever beam's modal properties, and electronic signal conditioning. Impact tests and FEM analysis were also carried out to verify the numerical simulation results. The results of impact tests indicate the excellent capability of the attached PVDF sensor in capturing the fundamental natural frequencies of the cantilever beam. There is a good agreement between the PVDF sensor's output voltage predicted by the numerical simulation and that obtained in the impact tests. Parametric studies were conducted to investigate the effects of sensor size and sensor position and it is shown that a larger sensor tends to generate higher output voltage than a smaller one at the same location. However, the effect of sensor location seems to be more significant for larger sensors due to the cancelling problem. Overall, PVDF sensors exhibit excellent sensing capability for in-plane dynamic strain induced by impact loading.

  1. NONLINEAR ANALYSIS OF CFRP- PRESTRESSED CONCRETE BEAMS SUBJECTED TO INCREMENTAL STATIC LOADING BY FINITE ELEMENTS

    Directory of Open Access Journals (Sweden)

    Husain M. Husain

    2013-05-01

    Full Text Available In this work a program is developed to carry out the nonlinear analysis (material nonlinearity of prestressed concrete beams using tendons of carbon fiber reinforced polymer (CFRP instead of steel. The properties of this material include high strength, light weight, and insusceptibility to corrosion and magnetism. This material is still under investigation, therefore it needs continuous work to make it beneficial in concrete design. Four beams which are tested experimentally by Yan et al. are examined by the developed computer program to reach a certain analytical approach of the design and analysis of such beams because there is no available restrictions or recommendations covering this material in the codes. The program uses the finite element analysis by dividing the beams into isoparametric 20-noded brick elements. The results obtained are good in comparison with experimental results.

  2. Interaction of a self-focused laser beam with a DT fusion target in a plasma-loaded cone-guided ICF scheme

    Science.gov (United States)

    Saedjalil, N.; Mehrangiz, M.; Jafari, S.; Ghasemizad, A.

    2016-06-01

    In this paper, the interaction of a self-focused laser beam with a DT fusion target in a plasma-loaded cone-guided ICF scheme has been presented. We propose here to merge a plasma-loaded cone with the precompressed DT target in order to strongly focus the incident laser beam on the core to improve the fusion gain. The WKB approximation is used to derive a differential equation that governs the evolution of beamwidth of the incident laser beam with the distance of propagation in the plasma medium. The effects of initial plasma and laser parameters, such as initial plasma electron temperature, initial radius of the laser beam, initial laser beam intensity and plasma density, on self-focusing and defocusing of the Gaussian laser beam have been studied. Numerical results indicate that with increasing the plasma frequency (or plasma density) in the cone, the laser beam will be self-focused noticeably, while for a thinner laser beam (with small radius), it will diverge as propagate in the cone. By evaluating the energy deposition of the relativistic electron ignitors in the fuel, the importance of electron transportation in the cone-attached shell was demonstrated. Moreover, by lessening the least energy needed for ignition, the electrons coupling with the pellet enhances. Therefore, it increases the fusion efficiency. In this scheme, with employing a plasma-loaded cone, the fusion process improves without needing an ultrahigh-intensity laser beam in a conventional ICF.

  3. Micromotion Compensation and Photoionization of Ions in a Linear Trap

    Institute of Scientific and Technical Information of China (English)

    XIE Yi; ZHOU Fei; CHEN Liang; WAN Wei; FENG Mang

    2011-01-01

    @@ e confinement of ions in an electromagnetic trap is a prerequisite of sideband cooling and quantum information processing.For a string of ions in a linear ion trap,we report our recent efforts of compensating for micromotion of the ions by three methods,which yields narrower fluorescence spectra and lower temperature.We also achieve a photoionization scheme that loads the ions deterministically into the linear trap from an atomic beam.%The stable confinement of ions in an electromagnetic trap is a prerequisite of sideband cooling and quantum information processing. For a string of ions in a linear ion trap, we report our recent efforts of compensating for micromotion of the ions by three methods, which yields narrower fluorescence spectra and lower temperature. We also achieve a photoionization scheme that loads the ions deterministically into the linear trap from an atomic beam.

  4. Vacuum tube operation analysis under multi-harmonic driving and heavy beam loading effect in J-PARC RCS

    Science.gov (United States)

    Yamamoto, M.; Nomura, M.; Shimada, T.; Tamura, F.; Hara, K.; Hasegawa, K.; Ohmori, C.; Toda, M.; Yoshii, M.; Schnase, A.

    2016-11-01

    An rf cavity in the J-PARC RCS not only covers the frequency range of a fundamental acceleration pattern but also generates multi-harmonic rf voltage because it has a broadband impedance. However, analyzing the vacuum tube operation in the case of multi-harmonics is very complicated because many variables must be solved in a self-consistent manner. We developed a method to analyze the vacuum tube operation using a well-known formula and which includes the dependence on anode current for some variables. The calculation method is verified with beam tests, and the results indicate that it is efficient under condition of multi-harmonics with a heavy beam loading effect.

  5. Margin selection to compensate for loss of target dose coverage due to target motion during external-beam radiation therapy of the lung.

    Science.gov (United States)

    Foster, W Kyle; Osei, Ernest; Barnett, Rob

    2015-01-08

    The aim of this study is to provide guidelines for the selection of external-beam radiation therapy target margins to compensate for target motion in the lung during treatment planning. A convolution model was employed to predict the effect of target motion on the delivered dose distribution. The accuracy of the model was confirmed with radiochromic film measurements in both static and dynamic phantom modes. 502 unique patient breathing traces were recorded and used to simulate the effect of target motion on a dose distribution. A 1D probability density function (PDF) representing the position of the target throughout the breathing cycle was generated from each breathing trace obtained during 4D CT. Changes in the target D95 (the minimum dose received by 95% of the treatment target) due to target motion were analyzed and shown to correlate with the standard deviation of the PDF. Furthermore, the amount of target D95 recovered per millimeter of increased field width was also shown to correlate with the standard deviation of the PDF. The sensitivity of changes in dose coverage with respect to target size was also determined. Margin selection recommendations that can be used to compensate for loss of target D95 were generated based on the simulation results. These results are discussed in the context of clinical plans. We conclude that, for PDF standard deviations less than 0.4 cm with target sizes greater than 5 cm, little or no additional margins are required. Targets which are smaller than 5 cm with PDF standard deviations larger than 0.4 cm are most susceptible to loss of coverage. The largest additional required margin in this study was determined to be 8 mm.

  6. Beam patterns in an optical parametric oscillator set-up employing walk-off compensating beta barium borate crystals

    Science.gov (United States)

    Kaucikas, M.; Warren, M.; Michailovas, A.; Antanavicius, R.; van Thor, J. J.

    2013-02-01

    This paper describes the investigation of an optical parametric oscillator (OPO) set-up based on two beta barium borate (BBO) crystals, where the interplay between the crystal orientations, cut angles and air dispersion substantially influenced the OPO performance, and especially the angular spectrum of the output beam. Theory suggests that if two BBO crystals are used in this type of design, they should be of different cuts. This paper aims to provide an experimental manifestation of this fact. Furthermore, it has been shown that air dispersion produces similar effects and should be taken into account. An x-ray crystallographic indexing of the crystals was performed as an independent test of the above conclusions.

  7. Exterior beam-column joint study with non-conventional reinforcement detailing using mechanical anchorage under reversal loading

    Indian Academy of Sciences (India)

    S Rajagopal; S Prabavathy

    2014-10-01

    Reinforced concrete structures beam-column joints are the most critical regions in seismic prone areas. Proper reinforcement anchorage is essential to enhance the performance of the joints. An attempt has been made to appraise the performance of the anchorages and joints. The anchorages are detailed as per ACI-352 (mechanical anchorages), ACI-318 (conventional bent hooks) and IS-456 (conventional full anchorage). The joints are detailed without confinement in group-I and with additional X-cross bar in group-II. To assess the seismic performance, the specimens are assembled into two groups of three specimens each and were tested under reversal loading, The specimen with T-type mechanical anchorage (Headed bar) and T-type mechanical anchorage combination with X-cross bar exhibited significant improvement in seismic performance: load-displacement capacity, displacement ductility, stiffness degradation, controlled crack capacity in the joint shear panel and also reduced congestion of reinforcement in joint core.

  8. Post-strengthening of reinforced concrete beams with prestressed CFRP strips: part 2: analysis under cyclic loading

    Directory of Open Access Journals (Sweden)

    M. R. Garcez

    Full Text Available Different FPR post-strengthening techniques have been developed and applied in existing structures aiming to increase their load capacity. Most of the FRP systems used nowadays consist of carbon fibers embedded in epoxy matrices (CFRP. Regardless of the advantages and the good results shown by the CFRP post-strengthen technique, experimental studies show that, in most cases, the failure of post-strengthened structures is premature. Aiming to better use the tensile strength of the carbon fiber strips used as post-strengthening material, the application of prestressed CFRP strips started to be investigated. The main purpose of this paper is to analyze the effects of the composite prestressing in the performance of the CFRP post strengthening technique. The experimental program was based on flexural tests on post-strengthened reinforced concrete beams subjected to static - part 1 and cyclic - part 2 loading. Experimental results allowed the analysis of the quality and shortcomings of post-strengthen system studied, which resulted in valuable considerations about the analyzed post-strengthened beams.

  9. Convergence of Galerkin truncation for dynamic response of finite beams on nonlinear foundations under a moving load

    Science.gov (United States)

    Ding, Hu; Chen, Li-Qun; Yang, Shao-Pu

    2012-05-01

    The present paper investigates the convergence of the Galerkin method for the dynamic response of an elastic beam resting on a nonlinear foundation with viscous damping subjected to a moving concentrated load. It also studies the effect of different boundary conditions and span length on the convergence and dynamic response. A train-track or vehicle-pavement system is modeled as a force moving along a finite length Euler-Bernoulli beam on a nonlinear foundation. Nonlinear foundation is assumed to be cubic. The Galerkin method is utilized in order to discretize the nonlinear partial differential governing equation of the forced vibration. The dynamic response of the beam is obtained via the fourth-order Runge-Kutta method. Three types of the conventional boundary conditions are investigated. The railway tracks on stiff soil foundation running the train and the asphalt pavement on soft soil foundation moving the vehicle are treated as examples. The dependence of the convergence of the Galerkin method on boundary conditions, span length and other system parameters are studied.

  10. Deflection and Supporting Force Analysis of a Slender Beam under Combined Transverse and Tensile Axial Loads

    Science.gov (United States)

    2016-05-01

    supporting force analysis of a static pressure pipe that is to be used in the Defence Science and Technology Group Transonic Wind Tunnel test...Technology Group Transonic Wind Tunnel test facility. The static pressure pipe analysed herein was modelled as a slender propped cantilever beam...the Defence Science and Technology Group Transonic Wind Tunnel facility. A layout diagram of the static pressure pipe installation is shown in

  11. Deserved Compensation

    Institute of Scientific and Technical Information of China (English)

    LI LI

    2010-01-01

    @@ China's National People's Congress (NPC), the top legislature, recently adopted amendments to the Law on State Compensation, granting citizens greater power to obtain compensation when their rights are violated by the state.

  12. Beam loading in the bubble regime in plasmas with hollow channels

    Science.gov (United States)

    Golovanov, A. A.; Kostyukov, I. Yu.; Thomas, J.; Pukhov, A.

    2016-09-01

    Based on the already existing analytical theory of the strong nonlinear wakefield (which is called "bubble") in transversely inhomogeneous plasmas, we study the particular behavior of non-loaded (empty) bubbles and bubbles with accelerated bunches. We obtain an analytical expression for the shape of a non-loaded bubble in a general case and verify it with particle-in-cell (PIC) simulations. We derive a method of calculating the acceleration efficiency for arbitrary accelerated bunches. The influence of flat-top electron bunches on the shape of a bubble is studied. It is also shown that it is possible to achieve the acceleration in a homogeneous longitudinal electric field by the adjustment of the longitudinal density profile of the accelerated electron bunch. The predictions of the model are verified by 3D PIC simulations and are in a good agreement with them.

  13. Beam loading in the bubble regime in plasmas with hollow channels

    CERN Document Server

    Golovanov, A A; Thomas, J; Pukhov, A

    2016-01-01

    Based on the already existing analytical theory of the strongly-nonlinear wakefield (which is called "bubble") in transversely inhomogeneous plasmas, we study particular behavior of non-loaded (empty) bubbles and bubbles with accelerated bunches. We obtain an analytical expression for the shape of a non-loaded bubble in a general case and verify it with particle-in-cell (PIC) simulations. We derive a method of calculation of the acceleration efficiency for arbitrary accelerated bunches. The influence of flat-top electron bunches on the shape of a bubble is studied. It is also shown that it is possible to achieve acceleration in a homogeneous longitudinal electric field by the adjustment of the longitudinal density profile of the accelerated electron bunch. The predictions of the model are verified by 3D PIC simulations and are in a good agreement with them.

  14. 恒负载时转速降落开环补偿方法与实验研究%Open-loop Speed Loss Compensation Method and Experiment Study under Constant Load

    Institute of Scientific and Technical Information of China (English)

    乐南更; 彭天好; 张川; 许军; 王光洪

    2012-01-01

    分析变转速泵控马达调速系统转速降落的主要原因,指出系统泄漏和电机机械特性均能引起转速降落,推导出转速降落补偿系数表达式,建立了恒负载时变转速泵控马达调速系统转速降落补偿方法.实验结果表明:在恒负载时,采用所提出的补偿方法能够很好地实现转速降落补偿.%The reasons of motor speed loss in variable-speed pump-control-motor governing system were analyzed. It was pointed out that system leakage and electromotor mechanical properties were the reasons. Speed drop compensation coefficient expression was derived, and the compensation method under constant load in variable-speed pump-control-motor governing system was built. The experiment results show that using this compensation method, motor speed loss in constant load can be compensated.

  15. Seismic Behavor of RC Beam-Column Joint with Additional Bars under Cyclic Loading

    Institute of Scientific and Technical Information of China (English)

    LU Xilin; Tonny H.URUKAP; LI Sen

    2011-01-01

    The behavior of Beam-Column Joints in moment resisting frame structures are susceptible to damage caused by seismic effects due to poor performance of the joint. A good number of researches were carried out to understand the complex mechanism of RC joints which are considered in seismic design code practices presently adopted. The traditional construction detailing of transverse reinforcement have shown serious joint failure.This paper introduces a new design philosophy involving the use of additional diagonal bars within the joint particularly suitable for low to medium seismic effects in earthquake zones throughout the world. In lieu to this study, ten (10) full-scale interior beam-column specimens were constructed with various additional reinforcement details and configurations as will be discussed in the later. The experiment provided adequate results to proof the idea of additional bars as suitable approach in reinforced concrete structures where earthquake is eminent. While compared with overall cracking observation during the test, the specimen with additional bars (diagonal and straight) had shown few cracks on the column than the ones without. Furthermore, concrete confinement is certainly an important design method as recommended by certain international codes.

  16. Numerical Simulation of Output Response of PVDF Sensor Attached on a Cantilever Beam Subjected to Impact Loading

    Directory of Open Access Journals (Sweden)

    Cao Vu Dung

    2016-04-01

    Full Text Available Polyvinylidene Flouride (PVDF is a film-type polymer that has been used as sensors and actuators in various applications due to its mechanical toughness, flexibility, and low density. A PVDF sensor typically covers an area of the host structure over which mechanical stress/strain is averaged and converted to electrical energy. This study investigates the fundamental “stress-averaging” mechanism for dynamic strain sensing in the in-plane mode. A numerical simulation was conducted to simulate the “stress-averaging” mechanism of a PVDF sensor attached on a cantilever beam subjected to an impact loading, taking into account the contribution of piezoelectricity, the cantilever beam’s modal properties, and electronic signal conditioning. Impact tests and FEM analysis were also carried out to verify the numerical simulation results. The results of impact tests indicate the excellent capability of the attached PVDF sensor in capturing the fundamental natural frequencies of the cantilever beam. There is a good agreement between the PVDF sensor’s output voltage predicted by the numerical simulation and that obtained in the impact tests. Parametric studies were conducted to investigate the effects of sensor size and sensor position and it is shown that a larger sensor tends to generate higher output voltage than a smaller one at the same location. However, the effect of sensor location seems to be more significant for larger sensors due to the cancelling problem. Overall, PVDF sensors exhibit excellent sensing capability for in-plane dynamic strain induced by impact loading.

  17. Structure Compensation Control for Eliminating Extra Torque of Motor Drive Load Simulator%电动负载模拟器抑制多余力的结构补偿控制

    Institute of Scientific and Technical Information of China (English)

    李瑞; 王明艳

    2013-01-01

    Extra torque existing in the motor drive load simulator influences the load precision and system stability. Aiming at the problem,based on the work principle and structure,the model of the load system was built and the structure compensation unit was designed. The limitations of the conventional compensation methods were analyzed,and an improved compensation method of structure invariance was proposed. The compound control method was used to design the entire control system. The simulation results indicate using the method,the extra torque can be reduced greatly. It has some feasibility in engineering.%  电动负载模拟器存在多余力矩,且严重影响加载精度和系统的稳定性。针对此问题,在分析加载系统基本结构和原理的基础上,建立加载系统模型,设计结构补偿环节;分析常规补偿方法的局限性,提出改进的结构不变性补偿方法,并用复合控制方法来设计控制系统。仿真结果表明:此方法能够大幅度消除多余力矩,且在工程中有一定的可行性。

  18. Analyzer of high-load electron beams with resolution in two energy components, space and time

    Directory of Open Access Journals (Sweden)

    Alexander V. Arkhipov

    2015-03-01

    Full Text Available The new apparatus is developed for experimental determination of electron energy and spatial distributions in dense medium-energy long-pulsed magnetically confined beams – typically, 10 A/cm2, 60 keV, 100 µs, 0.1 T. To provide most detailed and unambiguous information, direct electrostatic cut-off method is used for electron energy analysis. In combination with variation of the magnetic field in the analysis area, this method allows to determine both (axial and transverse components of electron energy. Test experiments confirmed ∼1% energy resolution being predicted from calculations, accounting for electrode shapes, space-charge effects and non-adiabatic energy transfer effects in varied magnetic field. Space and time resolution of the apparatus are determined by the input aperture size (∼1 mm and cut-off electric field pulse-length (∼5–10 µs respectively.

  19. Application of the differential transformation method and variational iteration method to large deformation of cantilever beams under point load

    Energy Technology Data Exchange (ETDEWEB)

    Salehi, Pouya [Semnan Univ., Semnan (Iran, Islamic Republic of); Yaghoobi, Hessamed Din; Torabi, Mohsen [City Univ. of Hong Kong, Hong Kong (China)

    2012-09-15

    Large deflection of a cantilever beam subjected to a tip concentrated load is governed by a non-linear differential equation. Since it is hard to find exact or closed form solutions for this non-linear problem, this paper investigates the aforementioned problem via the differential transformation method (DTM) and the variational iteration method (VIM), which are well known approximate analytical solutions. The mathematical formulation is yielded to a non-linear two-point boundary value problem. In this study, we compare the DTM and VIM results, with those of Adomian decomposition method (ADM) and the established numerical solution obtained by the Richardson extrapolation in order to verify the accuracy of the proposed methods. As an important result, it is depicted from tabulated data that the DTM results are more accurate in comparison with those obtained by the VIM and ADM, which is one of the objectives of this article. Moreover, the effects of dimensionless end point load, {alpha} , on the slope of any point along the arc length and the dimensionless vertical and horizontal displacements are illustrated and explained. The results reveal that these methods are very effective and convenient in predicting the solution of such problems, and it is predicted that the DTM and VIM can find a wide application in new engineering problems.

  20. A Novel Compensator Used in Traction Substation for Load Balancing%一种用于电铁牵引变电站负荷平衡的新型补偿器

    Institute of Scientific and Technical Information of China (English)

    戚庆茹; 张春朋

    2012-01-01

    随着我国电气化高速铁路的发展,牵引供电系统对电网带来的负面影响不容忽视.提出了一种用于电铁牵引变二次侧的新型换流补偿器,通过定义一个虚拟的三相系统并采用分相控制策略,实现动态跟踪并平衡两相牵引桥臂上的负荷,进而从根本上消除牵引变对三相交流系统的负序干扰,并且该补偿器还具备动态无功调节功能.仿真结果证明,本文提出的新型补偿器既可以有效平衡牵引变电所不同桥臂上的负荷,消除电铁牵引变向电网注入的负序电流,还可以通过补偿器实现牵引站的动态无功补偿.%With the rapid development of electrified railway, the negative influence of traction power system on power grid is indispensable. A novel compensator used in traction substation is proposed in this paper, and a virtual three-phase control strategy is designed for this compensator to dynamically track and balance the load of traction supply arms by phase-separation control strategy. Then, negative sequence disturbances of three-phase AC system caused by traction system are eliminated, and this compensator can also regulate reactive power of the traction substation. Simulation results show that this novel compensator can not only balance the loads of two traction supply arms, but also realize reactive power compensation efficiently.

  1. Distortional solutions for loaded semi-discretized thin-walled beams

    DEFF Research Database (Denmark)

    Andreassen, Michael Joachim; Jönsson, Jeppe

    2012-01-01

    distortional displacement fields which decouple the reduced order differential equations. In this process the cross section is discretized into finite cross-section elements, and the natural distortional modes as well as the related axial variations are found as solutions to the established coupled fourth...... order homogeneous differential equations of GBT.In this paper the non-homogeneous distortional differential equations of GBT are formulated using this novel semi-discretization process. Transforming these non-homogeneous distortional differential equations into the natural eigenmode space by using...... the distortional modal matrix found for the homogeneous system, we get the uncoupled set of differential equations including the distributed loads. This uncoupling is very important in GBT, since the shear stiffness contribution from St. Venant torsional shear stress as well as “Bredt's shear flow” cannot...

  2. Determining large deflections in rectangular combined loaded cantilever beams made of non-linear Ludwick type material by means of different arc length assumptions

    Indian Academy of Sciences (India)

    Ibrahim Eren

    2008-02-01

    In this study, large deflection of cantilever beams of Ludwick type material subjected to a combined loading consisting of a uniformly distributed load and one vertical concentrated load at the free end was investigated. In calculations, both material and geometrical non-linearity have been considered. Horizontal and vertical deflections magnitudes were calculated throughout Euler–Bernoulli curvature-moment relationship assuming different arc lengths. Vertical deflections were calculated by using Runge–Kutta method. More simple and easily understandable results have been obtained compared to the previous studies about the issue and compatible values have been obtained for most of the compared values.

  3. Coupled bending-torsion vibration of a homogeneous beam with a single delamination subjected to axial loads and static end moments

    Science.gov (United States)

    Liu, Yang; Shu, Dong-Wei

    2014-08-01

    Delaminations in structures may significantly reduce the stiffness and strength of the structures and may affect their vibration characteristics. As structural components, beams have been used for various purposes, in many of which beams are often subjected to axial loads and static end moments. In the present study, an analytical solution is developed to study the coupled bending-torsion vibration of a homogeneous beam with a single delamination subjected to axial loads and static end moments. Euler-Bernoulli beam theory and the "free mode" assumption in delamination vibration are adopted. This is the first study of the influences of static end moments upon the effects of delaminations on natural frequencies, critical buckling loads and critical moments for lateral instability. The results show that the effects of delamination on reducing natural frequencies, critical buckling load and critical moment for lateral instability are aggravated by the presence of static end moment. In turn, the effects of static end moments on vibration and instability characteristics are affected by the presence of delamination. The analytical results of this study can serve as a benchmark for finite element method and other numerical solutions.

  4. Survival of patients with intermediate stage hepatocellular carcinoma treated with superselective transarterial chemoembolization using doxorubicin-loaded DC Bead under cone-beam computed tomography control

    Directory of Open Access Journals (Sweden)

    Popovic Peter

    2016-12-01

    Full Text Available The purpose of this retrospective study was to evaluate treatment response, adverse events and survival rates of patients with intermediate stage HCC treated with superselective doxorubicin-loaded DC Bead transarterial chemoembolization (DEBDOX under cone beam computed tomography (CBCT control.

  5. DEFLECTION OF A HETEROGENEOUS WIDE-BEAM UNDER UNIFORM PRESSURE LOAD

    Energy Technology Data Exchange (ETDEWEB)

    T. V. Holschuh; T. K. Howard; W. R. Marcum

    2014-07-01

    Oregon State University (OSU) and the Idaho National Laboratory (INL) are currently collaborating on a test program which entails hydro-mechanical testing of a generic plate type fuel element, or generic test plate assembly (GTPA), for the purpose of qualitatively demonstrating mechanical integrity of uranium-molybdenum monolithic plates as compared to that of uranium aluminum dispersion, and aluminum fuel plates onset by hydraulic forces. This test program supports ongoing work conducted for/by the Global Threat Reduction Initiative (GTRI) Fuels Development Program. This study’s focus supports the ongoing collaborative effort by detailing the derivation of an analytic solution for deflection of a heterogeneous plate under a uniform, distributed load in order to predict the deflection of test plates in the GTPA. The resulting analytical solutions for three specific boundary condition sets are then presented against several test cases of a homogeneous plate. In all test cases considered, the results for both homogeneous and heterogeneous plates are numerically identical to one another, demonstrating correct derivation of the heterogeneous solution. Two additional problems are presents herein that provide a representative deflection profile for the plates under consideration within the GTPA. Furthermore, qualitative observations are made about the influence of a more-rigid internal fuel-meat region and its influence on the overall deflection profile of a plate. Present work is being directed to experimentally confirm the analytical solution’s results using select materials.

  6. Adaptive Motion Compensation in Radiotherapy

    CERN Document Server

    Murphy, Martin J

    2011-01-01

    External-beam radiotherapy has long been challenged by the simple fact that patients can (and do) move during the delivery of radiation. Recent advances in imaging and beam delivery technologies have made the solution--adapting delivery to natural movement--a practical reality. Adaptive Motion Compensation in Radiotherapy provides the first detailed treatment of online interventional techniques for motion compensation radiotherapy. This authoritative book discusses: Each of the contributing elements of a motion-adaptive system, including target detection and tracking, beam adaptation, and pati

  7. 无功和三相负荷不平衡的序分量法补偿控制%Compensation control of reactive power and three-phase unbalance load based on the method of sequence component

    Institute of Scientific and Technical Information of China (English)

    辛业春; 李国庆; 王朝斌

    2014-01-01

    A static synchronous compensator (STATCOM) is used into distribution grid for compensating reactive power and three- phase unbalance load for the distribution grid. According to analyzing the positive sequence equivalent circuit and negative sequence equivalent circuit under the three-phase unbalance load of distribution grid, using the symmetrical component method and superposition principle, a new cascade loop control strategy of positive sequence current and negative sequence current is proposed. Usingδ-θ control, the positive sequence loop compensates reactive power of distribution grid and maintains stability of STATCOM DC voltage. Usingφ-θ control in the negative sequence loop can make STATCOM compensate negative-sequence current caused by three-phase load unbalance and keep distribution grid side three-phase load balanced. Simulation and experiment results are presented to verify the validity of the proposed control strategy. This work is supported by National Natural Science Foundation of China (No. 51377016).%将静止同步补偿器(Static Synchronous Compensator,STATCOM)并入电网来补偿无功功率和配电网三相负荷不平衡。通过对称分量法和叠加原理,对配电网三相负荷不平衡情况下正序、负序等效电路进行分析,提出一种新的正、负序补偿电流叠加补偿控制方法。正序控制环采用δ-θ控制,实现配电网无功功率补偿和保持STATCOM直流侧电压稳定;负序控制环采用φ-θ控制,实现STATCOM补偿三相负荷不平衡产生的负序电流,使电网侧三相负荷保持平衡。仿真和实验结果表明,该方法可以有效地补偿电网无功功率和三相负荷不平衡。

  8. The error compensation of the CNC punching line for truck U-beam%汽车U型纵梁数控冲孔线的加工误差补偿

    Institute of Scientific and Technical Information of China (English)

    刘林林; 陈晓倩; 李松福; 郝毅

    2012-01-01

    The principle of error compensation of the CNC punching line for truck U-beam has been introduced. By considering of all the factors which influence the machining accuracy, the problems during error compensation process have been analyzed. Then the improving method has been put forward, which can raise the productivity and accuracy of the production line.%介绍了汽车U型纵粱数控冲孔线加工误差补偿原理.综合影响机床加工精度的因素,对误差补偿过程中存在的问题进行分析,并提出改进办法,以提高设备的生产效率和加工精度.

  9. Load Feedforward and Feedback Compounded Compensation Control for Variable Speed Hydraulic Power Supply%变转速液压动力源的负载前馈反馈复合补偿控制

    Institute of Scientific and Technical Information of China (English)

    李昭; 谷立臣; 马玉

    2016-01-01

    研究了前馈控制和反馈控制的原理及优缺点,提出采用负载前馈反馈复合补偿控制策略实现液压动力源在典型工况下的恒流量控制.以变转速机电液系统实验平台为基础,建立变转速液压动力源的Simulink仿真模型,分别在简单PID反馈控制和复合补偿控制策略下进行仿真和实验,结果证明了该复合补偿控制策略在液压动力源恒流量控制中的可行性和有效性,其抗负载扰动性能明显优于简单PID反馈控制.%The principles and characteristics of feedforward control and feedback control were stud-ied,a method called the load feedforward and feedback compounded compensation control strategy was proposed herein to realize the constant flow control of hydraulic power supply under typical operating conditions.Based on the experimental platform of mechanical-electrical-hydraulic system,a Simulink model of variable speed hydraulic power supply was established.The simulations and experiments were carried out respectively under a simple PID feedback control and a compounded compensation control strategy.The results verify the compounded compensation control strategy is efficient and fea-sible in constant flow control of hydraulic power supply,and the resistance to load disturbance of the compounded compensation control strategy is superior to the simple PID control .

  10. Traction Substation Reactive Power Compensation Based on Dynamic On-Load Tap Changer%基于动态有载调压的牵引变电站无功补偿方法研究

    Institute of Scientific and Technical Information of China (English)

    张聂鹏; 杨旭

    2012-01-01

      Analysis was made to load characteristics of traction power supply system. This paper raised a method which adopt-ed on-load tap changer transformer to couple capacitor groups at substation side, compensating reactive power of power supply system. The dynamic on-load tap changer coupling reactive power compensation model was established and the control strategy was studied. Simulation result has verified the validity of the above mentioned method, which effectively raises power factor of substations and reduces operation loss.%  分析了牵引供电系统的负荷特性,提出了在变电站牵引侧通过有载调压变压器耦合电容器组来补偿牵引供电系统的无功功率的方法,建立了动态有载调压耦合无功补偿模型,并对控制策略进行了研究,仿真结果验证了所提方法的有效性,通过该方法可有效提高变电站的功率因数,降低运行损耗。

  11. Design of Motor-Driven Load Simulator Based on Improved Compensation Control Strategy%基于改进补偿控制策略的电动负载模拟器设计

    Institute of Scientific and Technical Information of China (English)

    李瑞; 王明艳; 张奥扬

    2013-01-01

      负载模拟器可以模拟飞行器飞行过程中受到的空气力矩,是重要的半实物仿真设备之一。针对电动负载模拟器存在的多余力矩,且严重影响了加载精度和系统的稳定性,通过在加载系统的基本结构和原理上,对加载系统进行建模,分析常规补偿法的局限性,提出改进的补偿方法,并用复合控制策略来设计控制系统。仿真结果表明,此方法能够大幅度消除多余力矩,且在工程中有一定的可行性。%Load simulator is an important equipment in hardware-in-the-loop simulation, which can simulate the air torque during aircraft flight. The extra torque existing in the motor-driven load simulator influenced the load precision and system stability. The model of load system is built based on the basic structure and principle of load system, the limitations of the conventional compensation method are analyzed, and the improved compensation method is proposed. The control system is designed by compound control strategy. The simulation results show that the method can greatly reduce the extra torque and can be used in the engineering.

  12. Beam screen cryogenic control improvements for the LHC run 2

    CERN Document Server

    Bradu, Benjamin; Blanco Vinuela, Enrique; Ferlin, Gerard; Tovar-Gonzalez, Antonio

    2016-01-01

    This paper presents the improvements made on the cryogenic control system for the LHC beam screens. The regulation objective is to maintain an acceptable temperature range around 20 K which simultaneously ensures a good LHC beam vacuum and limits cryogenic heat loads. In total, through the 27 km of the LHC machine, there are 485 regulation loops affected by beam disturbances. Due to the increase of the LHC performance during Run 2, standard PID controllers cannot keeps the temperature transients of the beam screens within desired limits. Several alternative control techniques have been studied and validated using dynamic simulation and then deployed on the LHC cryogenic control system in 2015. The main contribution is the addition of a feed-forward control in order to compensate the beam effects on the beam screen temperature based on the main beam parameters of the machine in real time.

  13. 基于串联补偿的细粒度能馈式虚拟负载研究%Research on the Virtual Load With Energy Feedback Based on the Series Compensation of the High-Accuracy

    Institute of Scientific and Technical Information of China (English)

    游菲; 袁旭峰; 胡晟; 陈磊; 欧家祥; 张秋雁

    2016-01-01

    1This paper presents a new virtual load with energy feedback based on high-accuracy series compensation. A single-phase load is established firstly; and based on the topology, three-phase four-wire series compensation virtual load with energy feedback is founded. The single phase load uses main circuit topology with its AC side inductor consisting of a series capacitor and a series inductor. This topology solves effectively the problem that the required power transmission capacity cannot be met and transient current cannot be traced at the same time when choosing reactor parameter in AC side, and improves minimum value accuracy in virtual load simulation. Controller of load converter and feedback converter are designed using Quasi-PR technology. Finally, simulation model and control strategy of virtual load are constructed in PSCAD and a prototype is built. Results of simulation and experiment verify feasibility and effectiveness of the proposed method.%提出一种基于串联补偿的细粒度能馈式虚拟负载,文章首先建立单相负载,并以此为基础构建三相四线制串联补偿的细粒度能馈式虚拟负载,单相负载采用一种串联电容与串联电感来构成交流侧电抗的能馈式虚拟负载主电路拓扑结构,有效克服交流侧电感参数选择时不能同时满足功率传输容量及瞬态电流跟踪要求的缺陷,提高了虚拟负载模拟负载最小粒度的精度。利用准 PR 控制技术,设计了虚拟负载负载换流器(load converter,LC)和能馈换流器(feedback converter,FC)的控制器。最后,利用 PSCAD 软件构建了仿真模型及控制策略并搭建一套样机,通过仿真及实验结果验证了其可行性和有效性。

  14. Creative compensation

    Energy Technology Data Exchange (ETDEWEB)

    Coll, D

    1994-09-19

    A discussion is presented of executive compensation in Canada's petroleum industry. Mandatory disclosure of executive compensation and benefits is regulated by the Ontario Securities Commission. Examination of the compensation packages of 80 oilpatch CEOs shows a clear difference in philosophy between large and small companies. Larger companies pay larger salaries, offer pension plans, and reward long-term loyalty. Within smaller companies, compensation tends to be linked with stock performance. Trends in compensation are to lower base salaries with more variables such as bonuses, cash incentives and gain-sharing programs. Increasing shareholder scrutiny is prompting more stringent guidelines on stock option plans. Some companies place performance conditions on stock vesting. Another option is to grant premium priced options to executives, to increase the gains required for the executive to post a profit. Other comapanies are granting stock options to their field personnel, or are granting stock to all employees. Directors are playing an increasing role in executive compensation. 4 tabs.

  15. 永磁直线伺服系统最优参数负载扰动补偿方法%Optimal Parameter Load Disturbance Compensation Method of Permanent Magnet Linear Servo System

    Institute of Scientific and Technical Information of China (English)

    王丽梅; 武志涛; 刘春芳

    2012-01-01

    For the direct drive permanent magnet linear synchronous motor(PMLSM) servo system,the load disturbance and the parameters changes will influence the performance of the servo system seriously.A disturbance compensation method of position controller combined with optimal parameter disturbance compensating controller was proposed.It ensured that the system had fast transient response and good load disturbance rejection capability.The position controller determined the transient response performance and the load compensator improved the ability of disturbance suppression.And by using the Parseval theorem,its parameters were obtained from an optimization technique that transformed the position deviation of the performance index from time domain into the frequency domain,and then the Routh-Hurwitz two-dimensional array was calculated to obtain the optimal proportional-integral parameters.The simulation and experimental results show that the proposed compensation method enhances control precision and robustness of the system.%对于直接驱动永磁直线伺服系统,负载扰动和系统参数的变化严重影响系统伺服性能。本文提出了一种位置控制器与负载扰动补偿器相结合的扰动抑制方法,该方法同时兼顾了直线伺服系统快速的瞬时响应和良好的抗干扰能力。其中位置控制器决定系统的瞬时响应特牲,而负载扰动补偿器则用来改善系统的抗干扰能力。在负载扰动补偿器的参数确定中提出利用Parseval定理中信号在时间域内的总能量与频域内的总能量相等的原理,将位置偏差量的时域性能指标转为频域性能指标,再通过对劳斯-赫尔维茨(Routh-Hurwitz)二维数组的计算,确定最优化PI参数。仿真结果与实验表明,该补偿方法使直线电机伺服系统具有良好的控制精度与鲁棒性。

  16. 杆式应变天平变负载动态建模和分段动态补偿%Dynamic modeling and staged compensation of bar-shaped strain gauge balance with changing load

    Institute of Scientific and Technical Information of China (English)

    周全; 徐科军; 杨双龙

    2012-01-01

    杆式应变天平安装在飞行器模型中,用于测量飞行器模型在风洞实验中所受的空气动力和力矩.模型相当于天平的负载.为了研究负载对天平动态特性的影响,通过改变天平上的配重砝码质量,进行不同负载下的天平动态标定实验.采用OE模型描述在不同负载下,天平各通道的数学模型.根据模型得到动态特征参数.通过曲线拟合,表示天平特征参数与负载质量之间的变化规律.为了保证在不同负载下,天平均具有较好的动态响应性能,提出依据负载变化的分段动态补偿的思路,实现对不同负载实验数据的动态补偿,取得较好效果.%In the wind tunnel experiment, bar-shaped strain gauge balance installed in aircraft model is used to measure the aerodynamic forces and moments applied to the aircraft model. The aircraft model can be regarded as the load of the balance. In order to research the effect of load on the dynamic characteristic of the balance, the dynamic calibration experiments are conducted with different loads that are realized by changing weights. The system identification method based on output error model is adopted to describe the dynamic mathematical models for various channels of the balance with different loads. Their dynamic characteristic parameters are obtained according to the models. The curve fitting method is used to present the varying pattern between the characteristic parameters of the balance and the mass of loads. A kind of staged dynamic compensation solution is proposed to ensure good dynamic response performance under different loads. It implements the dynamic compensation for experimental data of different loads, and achieves good results.

  17. Green's function and Bloch theory for the analysis of the dynamic response of a periodically supported beam to a moving load

    Science.gov (United States)

    Lassoued, R.; Lecheheb, M.; Bonnet, G.

    2012-08-01

    This paper describes an analytical method for the wave field induced by a moving load on a periodically supported beam. The Green's function for an Euler beam without support is evaluated by using the direct integration. Afterwards, it introduces the supports into the model established by using the superposition principle which states that the response from all the sleeper points and from the external point force add up linearly to give a total response. The periodicity of the supports is described by Bloch's theorem. The homogeneous system thus obtained represents a linear differential equation which governs rail response. It is initially solved in the homogeneous case, and it admits a no null solution if its determinant is null, this permits the establishment the dispersion equation to Bloch waves and wave bands. The Bloch waves and dispersion curves contain all the physics of the dynamic problem and the wave field induced by a dynamic load applied to the system is finally obtained by decomposition into Bloch waves, similarly to the usual decomposition into dynamic modes on a finite structure. The method is applied to obtain the field induced by a load moving at constant velocity on a thin beam supported by periodic elastic supports.

  18. Effects of edge beams on mechanic behavior under lateral load in reinforced concrete hollow slab-column structure

    Institute of Scientific and Technical Information of China (English)

    成洁筠; 杨建军; 唐小弟

    2008-01-01

    In order to get the formulae for calculating the equivalent frame width coefficient of reinforced concrete hollow slab-column structures with edge beam,the finite element structural program was used in the elastic analysis of reinforced concrete hollow slab-column structure with different dimensions to study internal relationship between effective beam width and the frame dimensions.In addition,the formulas for calculating the increasing coefficient of edge beam were also obtained.

  19. Reactive current compensation with hybrid circuit; Blindstromkompensation mit Hybridschaltung

    Energy Technology Data Exchange (ETDEWEB)

    Henning Mueller, Janitza

    2013-06-01

    Compensation systems for reactive currents have to reduce costs. However, at excessively enhanced harmonic loads compensation systems are quickly overloaded and even become cost drivers. Plants in reinforced construction and improved technology are required. During rapid load fluctuations, compensation systems can be controlled better with thyristor controllers instead of slow shooter.

  20. Coupling creep and damage in concrete under high sustained loading: Experimental investigation on bending beams and application of Acoustic Emission technique

    Directory of Open Access Journals (Sweden)

    Grondin F.

    2010-06-01

    Full Text Available Creep and damage in concrete govern the long-term deformability of concrete. Thus, it is important to understand the interaction between creep and damage in order to design reliable civil engineering structures subjected to high level loading during a long time. Many investigations have been performed on the influence of concrete mixture, the effect of the bond between the matrix and the aggregates, temperature, aging and the size effect on the cracking mechanism and fracture parameters of concrete. But there is a lack of results on the influence of the creep loading history. In the present paper, an experimental investigation on the fracture properties of concrete beams submitted to three point bending tests with high levels of sustained load that deals with creep is reported. The results aim first to investigate the ranges of variation of the time response due to creep damage coupled effects under constant load and secondly to evaluate the residual capacity after creep. For this purpose a series of tests were carried out on geometrically similar specimens of size 100x200x800mm with notch to depth ratio of 0.2 in all the test specimens. The exchange of moisture was prevented and beams were subjected to a constant load of 70% and 90% of the maximum capacity. Three point bending test were realized on specimen at the age of 28 days to determine the characteristics of concrete and the maximum load so we could load the specimens in creep. Threepoint bend creep tests were performed on frames placed in a climate controlled chamber [1]. Then after four months of loading, the beams subjected to creep were removed from the creep frames and then immediately subjected to three-point bending test loading up to failure with a constant loading rate as per RILEM-FMC 50 recommendations. The residual capacity on the notched beams and the evolution of the characteristics of concrete due to the basic creep was considered. The results show that sustained loading

  1. Coupling creep and damage in concrete under high sustained loading: Experimental investigation on bending beams and application of Acoustic Emission technique

    Science.gov (United States)

    Saliba, J.; Loukili, A.; Grondin, F.

    2010-06-01

    Creep and damage in concrete govern the long-term deformability of concrete. Thus, it is important to understand the interaction between creep and damage in order to design reliable civil engineering structures subjected to high level loading during a long time. Many investigations have been performed on the influence of concrete mixture, the effect of the bond between the matrix and the aggregates, temperature, aging and the size effect on the cracking mechanism and fracture parameters of concrete. But there is a lack of results on the influence of the creep loading history. In the present paper, an experimental investigation on the fracture properties of concrete beams submitted to three point bending tests with high levels of sustained load that deals with creep is reported. The results aim first to investigate the ranges of variation of the time response due to creep damage coupled effects under constant load and secondly to evaluate the residual capacity after creep. For this purpose a series of tests were carried out on geometrically similar specimens of size 100x200x800mm with notch to depth ratio of 0.2 in all the test specimens. The exchange of moisture was prevented and beams were subjected to a constant load of 70% and 90% of the maximum capacity. Three point bending test were realized on specimen at the age of 28 days to determine the characteristics of concrete and the maximum load so we could load the specimens in creep. Threepoint bend creep tests were performed on frames placed in a climate controlled chamber [1]. Then after four months of loading, the beams subjected to creep were removed from the creep frames and then immediately subjected to three-point bending test loading up to failure with a constant loading rate as per RILEM-FMC 50 recommendations. The residual capacity on the notched beams and the evolution of the characteristics of concrete due to the basic creep was considered. The results show that sustained loading had a strengthening

  2. Questioning Compensation

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Transparent management and open information needed for the fund set up to compensate victims of the 2008 Sanlu milk scandal Almost three years after the Sanlu milk scandal that caused thousands of infants in China to develop urinary disease after drinking melamine

  3. Free and Forced Vibrations of an Axially-Loaded Timoshenko Multi-Span Beam Carrying a Number of Various Concentrated Elements

    Directory of Open Access Journals (Sweden)

    Yusuf Yesilce

    2012-01-01

    Full Text Available In the existing reports regarding free and forced vibrations of the beams, most of them studied a uniform beam carrying various concentrated elements using Bernoulli-Euler Beam Theory (BET but without axial force. The purpose of this paper is to utilize the numerical assembly technique to determine the exact frequency-response amplitudes of the axially-loaded Timoshenko multi-span beam carrying a number of various concentrated elements (including point masses, rotary inertias, linear springs and rotational springs and subjected to a harmonic concentrated force and the exact natural frequencies and mode shapes of the beam for the free vibration analysis. The model allows analyzing the influence of the shear and axial force and harmonic concentrated force effects and intermediate concentrated elements on the dynamic behavior of the beams by using Timoshenko Beam Theory (TBT. At first, the coefficient matrices for the intermediate concentrated elements, an intermediate pinned support, applied harmonic force, left-end support and right-end support of Timoshenko beam are derived. After the derivation of the coefficient matrices, the numerical assembly technique is used to establish the overall coefficient matrix for the whole vibrating system. Finally, solving the equations associated with the last overall coefficient matrix one determines the exact dynamic response amplitudes of the forced vibrating system corresponding to each specified exciting frequency of the harmonic force. Equating the determinant of the overall coefficient matrix to zero one determines the natural frequencies of the free vibrating system (the case of zero harmonic force and substituting the corresponding values of integration constants into the related eigenfunctions one determines the associated mode shapes. The calculated vibration amplitudes of the forced vibrating systems and the natural frequencies of the free vibrating systems are given in tables for different values of

  4. 基于导数约束的称重传感器非线性误差补偿方法%Method for Compensation of Load Cell's Nonlinear Error Based on Derivatives Constraints

    Institute of Scientific and Technical Information of China (English)

    林海军; 王震宇; 林亚平; 汪鲁才

    2013-01-01

    电阻应变式称重传感器存在严重的非线性误差,直接影响称重结果的准确度。本文首先阐述了称重传感器的非线性误差机理与误差补偿原理,提出了一种基于导数约束的称重传感器非线性误差补偿方法。该方法根据称重传感器输入-输出特性曲线的单调递增性,构造神经网络补偿模型训练的约束条件,完成神经网络优化设计,弥补了因训练样本不足导致的网络泛化误差大的缺陷,同时讨论了惩罚因子对网络性能的影响。实验表明,采用这种基于导数约束神经网络补偿方法( DCNN方法)的称重传感器的非线性误差远小于补偿前的误差;同时当训练样本不足时,DCNN方法比传统训练方法(仅利用数据样本训练神经网络,DINN)具有更好的泛化能力,称重准确度更高。%The nonlinear error of the resistance strain gauge load cell has heavy nonlinear error,which will lead to the low accuracy of weighing results. In this paper,the mechanism of the load cell's nonlinear error is introduced and a method for compensation on the load cell's nonlinear error based on derivatives constraints neural network ( DCNN) is proposed. In this method,the monotonically increasing characteristic of load cell's input-output function is used to construct the constraint conditions of training and optimizing the error compensation model with neural network,which can decrease the model's generalization error because of the lack of its training samples. On the other hand,the model's performance affected by the punishing factor is discussed. The experimental results show that the nonlinear error of load cell with this proposed method is far less than that without compensation,and the DCNN's generalization ability is more advantageous than the DINN( i. e. training neural network by only using data samples and not any constraint condition) ,and the weighing results of load cell with DCNN are more accurate.

  5. Experimental Assessment on the Flexural Bonding Performance of Concrete Beam with GFRP Reinforcing Bar under Repeated Loading

    Directory of Open Access Journals (Sweden)

    Minkwan Ju

    2015-01-01

    Full Text Available This study intends to investigate the flexural bond performance of glass fiber-reinforced polymer (GFRP reinforcing bar under repeated loading. The flexural bond tests reinforced with GFRP reinforcing bars were carried out according to the BS EN 12269-1 (2000 specification. The bond test consisted of three loading schemes: static, monotonic, and variable-amplitude loading to simulate ambient loading conditions. The empirical bond length based on the static test was 225 mm, whereas it was 317 mm according to ACI 440 1R-03. Each bond stress on the rib is released and bonding force is enhanced as the bond length is increased. Appropriate level of bond length may be recommended with this energy-based analysis. For the monotonic loading test, the bond strengths at pullout failure after 2,000,000 cycles were 10.4 MPa and 6.5 MPa, respectively: 63–70% of the values from the static loading test. The variable loading test indicated that the linear cumulative damage theory on GFRP bonding may not be appropriate for estimating the fatigue limit when subjected to variable-amplitude loading.

  6. The feasibility of polychromatic cone-beam x-ray fluorescence computed tomography (XFCT) imaging of gold nanoparticle-loaded objects: a Monte Carlo study

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Bernard L; Cho, Sang Hyun, E-mail: scho@gatech.edu [Nuclear/Radiological Engineering and Medical Physics Programs, Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0405 (United States)

    2011-06-21

    A recent study investigated the feasibility to develop a bench-top x-ray fluorescence computed tomography (XFCT) system capable of determining the spatial distribution and concentration of gold nanoparticles (GNPs) in vivo using a diagnostic energy range polychromatic (i.e. 110 kVp) pencil-beam source. In this follow-up study, we examined the feasibility of a polychromatic cone-beam implementation of XFCT by Monte Carlo (MC) simulations using the MCNP5 code. In the current MC model, cylindrical columns with various sizes (5-10 mm in diameter) containing water loaded with GNPs (0.1-2% gold by weight) were inserted into a 5 cm diameter cylindrical polymethyl methacrylate phantom. The phantom was then irradiated by a lead-filtered 110 kVp x-ray source, and the resulting gold fluorescence and Compton-scattered photons were collected by a series of energy-sensitive tallies after passing through lead parallel-hole collimators. A maximum-likelihood iterative reconstruction algorithm was implemented to reconstruct the image of GNP-loaded objects within the phantom. The effects of attenuation of both the primary beam through the phantom and the gold fluorescence photons en route to the detector were corrected during the image reconstruction. Accurate images of the GNP-containing phantom were successfully reconstructed for three different phantom configurations, with both spatial distribution and relative concentration of GNPs well identified. The pixel intensity of regions containing GNPs was linearly proportional to the gold concentration. The current MC study strongly suggests the possibility of developing a bench-top, polychromatic, cone-beam XFCT system for in vivo imaging.

  7. The feasibility of polychromatic cone-beam x-ray fluorescence computed tomography (XFCT) imaging of gold nanoparticle-loaded objects: a Monte Carlo study

    Science.gov (United States)

    Jones, Bernard L.; Cho, Sang Hyun

    2011-06-01

    A recent study investigated the feasibility to develop a bench-top x-ray fluorescence computed tomography (XFCT) system capable of determining the spatial distribution and concentration of gold nanoparticles (GNPs) in vivo using a diagnostic energy range polychromatic (i.e. 110 kVp) pencil-beam source. In this follow-up study, we examined the feasibility of a polychromatic cone-beam implementation of XFCT by Monte Carlo (MC) simulations using the MCNP5 code. In the current MC model, cylindrical columns with various sizes (5-10 mm in diameter) containing water loaded with GNPs (0.1-2% gold by weight) were inserted into a 5 cm diameter cylindrical polymethyl methacrylate phantom. The phantom was then irradiated by a lead-filtered 110 kVp x-ray source, and the resulting gold fluorescence and Compton-scattered photons were collected by a series of energy-sensitive tallies after passing through lead parallel-hole collimators. A maximum-likelihood iterative reconstruction algorithm was implemented to reconstruct the image of GNP-loaded objects within the phantom. The effects of attenuation of both the primary beam through the phantom and the gold fluorescence photons en route to the detector were corrected during the image reconstruction. Accurate images of the GNP-containing phantom were successfully reconstructed for three different phantom configurations, with both spatial distribution and relative concentration of GNPs well identified. The pixel intensity of regions containing GNPs was linearly proportional to the gold concentration. The current MC study strongly suggests the possibility of developing a bench-top, polychromatic, cone-beam XFCT system for in vivo imaging.

  8. 均布荷载作用下悬臂粱非线性的初探%FIRST EXPLORATION OF CANTILEVER BEAM NONLINEARTY UNDER UNIFORM LOAD

    Institute of Scientific and Technical Information of China (English)

    黄思宜; 李文兴

    2012-01-01

    根据广义胡克定律作进一步理论推导,推导了在均布荷载作用下悬臂梁非线性,即考虑各向异性情形下的应力分量解析解。%In accordance with further theoretical derivation of the generalized Hooke's, derivation and cantilever beam nonlinearty under uniform load, taking into account anisotropy in situations of stress components analytical solutions.

  9. Compensation Techniques in Accelerator Physics

    Energy Technology Data Exchange (ETDEWEB)

    Sayed, Hisham Kamal [Old Dominion Univ., Norfolk, VA (United States)

    2011-05-01

    Accelerator physics is one of the most diverse multidisciplinary fields of physics, wherein the dynamics of particle beams is studied. It takes more than the understanding of basic electromagnetic interactions to be able to predict the beam dynamics, and to be able to develop new techniques to produce, maintain, and deliver high quality beams for different applications. In this work, some basic theory regarding particle beam dynamics in accelerators will be presented. This basic theory, along with applying state of the art techniques in beam dynamics will be used in this dissertation to study and solve accelerator physics problems. Two problems involving compensation are studied in the context of the MEIC (Medium Energy Electron Ion Collider) project at Jefferson Laboratory. Several chromaticity (the energy dependence of the particle tune) compensation methods are evaluated numerically and deployed in a figure eight ring designed for the electrons in the collider. Furthermore, transverse coupling optics have been developed to compensate the coupling introduced by the spin rotators in the MEIC electron ring design.

  10. Ion dynamics in plasma compensation scheme

    Energy Technology Data Exchange (ETDEWEB)

    Timofeev, I.V.; Lotov, K.V. E-mail: lotov@inp.nsk.su

    2002-06-11

    In this paper the ability of a plasma to compensate beam-induced fields at the interaction point of muon colliders is discussed. Among numerous factors that limit beam and plasma parameters for which a given compensation degree can be achieved, one of the most important limitations (the motion of plasma ions) is analyzed in details. It is found that this limitation is determined by an instability of the relative motion of plasma electrons and ions. It is shown that discussed parameters of ultimate muon colliders fall outside the applicability area of plasma compensation.

  11. Cylindrical Penning traps with dynamic orthogonalized anharmonicity compensation for precision experiments

    CERN Document Server

    Fei Xiang

    1999-01-01

    Harmonic potentials can be produced in cylindrical ion traps by means of dynamic orthogonalized anharmonicity compensation with use of two (or multiple) sets of compensation electrodes. One special example is for traps with multiple identical electrodes which are not only easy to construct and allow access to the center region of the trap for particle loading and releasing, laser beams, and microwaves, but also flexible in forming harmonic potential wells in many locations. The nested trap configuration and the side-by-side trap configuration are readily available in this special scheme. Analytical solutions for cylindrical traps with multiple sets of compensation potentials are presented. This work will be useful for studies involving Penning trap diagnostics, atomic and molecular interactions (including the production of antihydrogen atoms), accurate mass measurements of exotic particles, and precision measurements of the spin precession frequencies of trapped particles.

  12. Rectangular Laser Resonators with Astigmatic Compensation

    DEFF Research Database (Denmark)

    Skettrup, Torben

    2005-01-01

    An investigation of rectangular resonators with a view to the compensation of astigmatism has been performed. In order to have beam waists placed at the same positions in the tangential and sagittal planes, pairs of equal mirrors were considered. It was found that at least two concave mirrors...... are necessary to obtain compensation. Four-concave-mirror systems are most stable close to the quadratic geometry, although the symmetric quadratic resonator itself cannot be compensated for astigmatism. Using four equal concave mirrors, compensation of astigmatism can be obtained in two arms at the same time....... Usually several stability ranges are found for four-mirror resonators with pair-wise equal mirrors, and it is possible with these systems to obtain small compensated beam waist radii suitable for frequency conversion. Relevant formulae are given and several relevant examples are shown using simulation...

  13. Buckling and free vibration of shallow curved micro/nano-beam based on strain gradient theory under thermal loading with temperature-dependent properties

    Science.gov (United States)

    Rahmani, O.; Hosseini, S. A. H.; Ghoytasi, I.; Golmohammadi, H.

    2017-01-01

    In this study, influences of a uniform thermomechanical loading in buckling and free vibration of a curved FG microbeam have been investigated, based on strain gradient theory (SGT) theory and Timoshenko beam model. Distribution of structural materials varies continuously in thickness direction due to power-law exponent. Unlike classical models, this novel model employs three length scale parameters which can capture the size effect. This work is based on SGT theory and Timoshenko beam model. Governing equation of motion and associated boundary condition have been developed based on Hamilton's principle, which is the specified case of virtual work theorem. In continuance, final differential equations were solved by Navier's solution method and the results have been presented. Moreover, influences of dimensionless length-to-thickness ratio (aspect ratio), dimensionless length scale parameter, power-law exponent, temperature difference and arc angle for various values of mode numbers on natural frequency and critical temperature by considering temperature-dependent material properties have been investigated. In order to validate accomplished study, some of the results were compared with those of previous works. It has been concluded that applying a thermomechanical loading on a FG microbeam causes the natural frequency to become more sensitive about variations of geometrical, physical and mechanical properties and characteristics.

  14. A slow gravity compensated atom laser

    DEFF Research Database (Denmark)

    Kleine Büning, G.; Will, J.; Ertmer, W.

    2010-01-01

    We report on a slow guided atom laser beam outcoupled from a Bose–Einstein condensate of 87Rb atoms in a hybrid trap. The acceleration of the atom laser beam can be controlled by compensating the gravitational acceleration and we reach residual accelerations as low as 0.0027 g. The outcoupling me...

  15. 含负荷不平衡补偿的SVC复合控制方法研究%The Composite Control Method Research of the SVC with Unbalanced Load Compensation

    Institute of Scientific and Technical Information of China (English)

    李慧

    2012-01-01

    该文提出了一种通过加装带滤波器的静止无功补偿器(SVC),使负序引起的不平衡功率和谐波功率流入SVC,最终达到平衡系统目的的方法;提出基于前馈-反馈复合控制的SVC不平衡负荷补偿方法,将电压闭环控制与三相不平衡控制相结合、功率因数闭环控制与三相不平衡控制相结合,以达到适应各种工况的需求。最后,该文在SVC相关理论研究的基础上搭建了仿真模型,仿真结果表明该文提出控制方法的正确性和可行性。%Based on the analysis of three-phase unbalanced system's instantaneous power,this paper proposes a method that by installing SVC compensator with a filter to make the imbalance power caused by negative sequence and harmonic power flowing into the SVC and achieve the ultimate objective of a balanced system.A feedforward-feedback composite control method on the unbalanced load compensation of SVC is also given in this paper,which take the voltage loop control and three-phase unbalance control integrated as well as make power factor loop combining with the three-phase unbalanced control.It is proved that this method can meet the needs of various working conditions.The simulation model is built based on the SVC theory,simulation results show that this control method is correct and feasible.

  16. Power analysis of static VAr compensators

    Energy Technology Data Exchange (ETDEWEB)

    Quintela, F.R.; Arevalo, J.M.G.; Redondo, R.C. [Escuela Tecnica Superior de Ingenieria Industrial, Universidad de Salamanca, 37700 Bejar (Spain)

    2008-07-15

    Analysis of three-phase loads usually assume them to be three impedances in a star or triangle connection. This is the reason why obtained results can only be considered valid for passive loads, strictly speaking. Analysis leading to the proposal of some static compensators is usually performed in this way, which induces to believe that this compensators are only valid for passive loads. An analysis procedure, which uses only powers to describe loads, is expounded in this paper. If applied to the analysis of static compensators, it reveals unequivocally their usefulness with active and passive three-phase loads. Therefore, this method is more general and, as it will be seen, easier. (author)

  17. Examination of material performance of W exposed to high heat load: Postmortem analysis of W exposed to TEXTOR plasma and E-beam test stand

    Science.gov (United States)

    Tanabe, T.; Philipps, V.; Nakamura, K.; Fujine, M.; Ueda, Y.; Wada, M.; Schweer, B.; Pospieszczyk, A.; Unterberg, B.

    1997-02-01

    We have examined the behavior of high Z limiters exposed to TEXTOR edge plasma and found that under certain conditions high Z materials are compatible with plasmas. In high density Ohmic plasmas the accumulation of a high Z impurity in the plasma center with significant radiation is observed, whereas an auxiliary heating like NBI and ICRH enhances the impurity exhaust with saw tooth activity. For a practical use of high Z plasma facing materials, extremely high heat load from the plasma becomes a serious concern. In the present work we have conducted the high heat load tests of tungsten (W) using two different heat sources, one is the W limiter exposed to TEXTOR plasma and the other is various W samples heat loaded with an intense E-beam using the JEBIS facility in Japan Atomic Energy Research Institute (JAERI). From the test results we have to conclude that W, if applied in the form of the bulk material, should be used above the ductile brittle transition temperature (DBTT) but below about 1500°C to avoid the recrystallization. Maximum heat load tolerable without surface melting is about 20 MW/m 2 for several seconds. The monocrystalline used at high temperatures shows very good performance, though the production of the monocrystalline with a desired shape is not easy. Considering its brittle nature, hard machining and heavy mass, bulk W cannot be a structure material but be used as a thin tile or deposited film on some structure materials. Unfortunately, however, the thermal expansion coefficient of W is so small that brazing of W to a heat sink material like Cu which has a much larger thermal expansion coefficient would easily result in cracking due to the large thermal stress. Thus the development of tungsten plasma facing component (PFC) needs much effort in future.

  18. 区域集中供冷项目10 kV冷水机组专用变压器空载补偿探讨%District Cooling Project of Special Transformer for 10 kV Cold Water Unit No-load Compensation

    Institute of Scientific and Technical Information of China (English)

    叶宏伟

    2015-01-01

    The research on the system of district cooling project of 10 kV 20/10 kV-10 000 kVA chiller special transformer deployment method and reactive power compensation system is set up, and using the interaction of cutting the capacitive reactive compensation system and play a resistance of reactive power compensation for the first time a full electromagnetic, effectively solves the system reactive power the compensated demand in the no-load and full load when the great difference of reactive power compensation demand problem.%研究了区域集中供冷项目10 kV冷水机组专用20/10 kV-10000 kVA变压器的系统部署方法和无功补偿系统的设置,并采用了全电磁一次投切的容性无功补偿系统和发挥了抗性无功补偿的相互作用,有效解决了系统在空载时无功补偿需求与全负荷时无功补偿需求的巨大差异问题。

  19. AN EXACT ELASTO-PLASTIC SOLUTION OF METAL-MATRIX COMPOSITE CANTILEVER BEAM LOADED BY A SINGLE FORCE AT ITS FREE END

    Directory of Open Access Journals (Sweden)

    Onur SAYMAN

    2001-03-01

    Full Text Available In the present study, an elastic-plastic stress analysis is carried out in a metal matrix composite cantilever beam loaded by a single force at its free end. A composite consisting of stainless-steel reinforced aluminium was produced for this work. The orientation angle of the fibers is chosen as 0°, 30°, 45°, 60° and 90°. The material is assumed to be perfectly plastic in the elasto-plastic solution. An analytical solution is performed for satisfying both the governing differential equation in the plane stress case and boundary conditions for small plastic deformations. The solution is carried out under the assumption of the Bernoulli-Navier hypotheses. The composite material is assumed as hardening linearly. The Tsai-Hill theory is used as a yield criterion.

  20. High-power radio frequency pulse generation and extration based on wakefield excited by an intense charged particle beam in dielectric-loaded waveguides.

    Energy Technology Data Exchange (ETDEWEB)

    Gao, F.; High Energy Physics; Illinois Inst. of Tech

    2009-07-24

    Power extraction using a dielectric-loaded (DL) waveguide is a way to generate high-power radio frequency (RF) waves for future particle accelerators, especially for two-beam-acceleration. In a two-beam-acceleration scheme, a low-energy, high-current particle beam is passed through a deceleration section of waveguide (decelerator), where the power from the beam is partially transferred to trailing electromagnetic waves (wakefields); then with a properly designed RF output coupler, the power generated in the decelerator is extracted to an output waveguide, where finally the power can be transmitted and used to accelerate another usually high-energy low-current beam. The decelerator, together with the RF output coupler, is called a power extractor. At Argonne Wakefield Accelerator (AWA), we designed a 7.8GHz power extractor with a circular DL waveguide and tested it with single electron bunches and bunch trains. The output RF frequency (7.8GHz) is the sixth harmonic of the operational frequency (1.3GHz) of the electron gun and the linac at AWA. In single bunch excitation, a 1.7ns RF pulse with 30MW of power was generated by a single 66nC electron bunch passing through the decelerator. In subsequent experiments, by employing different splitting-recombining optics for the photoinjector laser, electron bunch trains were generated and thus longer RF pulses could be successfully generated and extracted. In 16-bunch experiments, 10ns and 22ns RF pulses have been generated and extracted; and in 4-bunch experiments, the maximum power generated was 44MW with 40MW extracted. A 26GHz DL power extractor has also been designed to test this technique in the millimeter-wave range. A power level of 148MW is expected to be generated by a bunch train with a bunch spacing of 769ps and bunch charges of 20nC each. The arrangement for the experiment is illustrated in a diagram. Higher-order-mode (HOM) power extraction has also been explored in a dual-frequency design. By using a bunch

  1. Re-planning for compensator-based IMRT with original compensators.

    Science.gov (United States)

    Zhang, Geoffrey; Feygelman, Vladimir; Stevens, Craig; Li, Weiqi; Leuthold, Susan; Springett, Gregory; Hoffe, Sarah

    2011-01-01

    Compared with multileaf collimator (MLC)-based intensity-modulated radiotherapy (IMRT) for moving targets, compensator-based IMRT has advantages such as shorter beam-on time, fewer monitor units with potentially decreased secondary carcinogenesis risk, better optimization-to-deliverable dose conversion, and often better dose conformity. Some of the disadvantages include additional time for the compensators to be built and delivered, as well as extra cost. Patients undergoing treatment of abdominal cancers often experience weight loss. It would be necessary to account for this change in weight with a new plan and a second set of compensators. However, this would result in treatment delays and added costs. We have developed a method to re-plan the patient using the same set of compensators. Because the weight changes seen with the treatment of abdominal cancers are usually relatively small, a new 4D computed tomography (CT) acquired in the treatment position with markers on the original isocenter tattoos can be registered to the original planning scan. The contours of target volumes from the original scans are copied to the new scan after fusion. The original compensator set can be used together with a few field-in-field (FiF) beams defined by the MLC (or beams with cerrobend blocks for accelerators not equipped with a MLC). The weights of the beams with compensators are reduced so that the FiF or blocked beams can be optimized to mirror the original plan and dose distribution. Seven abdominal cancer cases are presented using this technique. The new plan on the new planning CT images usually has the same dosimetric quality as the original. The target coverage and dose uniformity are improved compared with the plan without FiF/block modification. Techniques combining additional FiF or blocked beams with the original compensators optimize the treatment plans when patients lose weight and save time and cost compared with generating plans with a new set of compensators.

  2. Small Angle Crab Compensation for LHC IR Upgrade

    CERN Document Server

    Akai, K; Dorda, U; Ohmi, K; Oide, K; Tomás, R; Zimmermann, T

    2007-01-01

    A small angle crab scheme is being considered for the LHC luminosity upgrade. In this paper we present a 400MHz superconducting cavity design and discuss the pertinent RF challenges. We also present a study on the beam-beam performance and proton-beam emittance growth in the presence of crab compensation, with RF noise sources.

  3. Faculty Compensation Policies.

    Science.gov (United States)

    Silander, Fred

    1983-01-01

    Faculty compensation policy is seen as one means by which an institution influences the faculty to work toward institutional goals. Among the broad criteria for compensation are worth, equity, need, and market measures. Benefits and issues in compensation including differentials in compensation, merit, part-time instruction, etc. are discussed.…

  4. Teoría generalizada de la potencia instantánea aplicada a la compensación de cargas polifásicas Generalized instantaneous power theory applied to multiphase loads compensation

    Directory of Open Access Journals (Sweden)

    Armando Jaime Ustariz-Farfan

    2012-08-01

    Full Text Available El interés creciente de utilizar filtros activos de potencia para compensar las corrientes no sinusoidales producidas por las cargas no lineales ha aumentado el uso de la teoría instantánea de potencia reactiva. Sin embargo, esta teoría se puede aplicar solamente a los sistemas trifásicos de tres o cuatro conductores. Este artículo presenta una nueva definición de la potencia instantánea que puede ser aplicada a todos los sistemas polifásicos. Así, el concepto de producto tensorial es introducido para definir el tensor instantáneo de potencia y también la descomposición de la corriente en las componentes activas y reactivas sin importar el número de fases del sistema eléctrico. Finalmente, un análisis exhaustivo de casos prácticos se ha realizado a nivel de simulación, los cuales han permitido que el enfoque propuesto sea verificado.The use of the instantaneous reactive power theory is greater than before due to the increased interest to use active power filters to compensate the non-sinusoidal currents produced by nonlinear loads. However, this theory can only be applied to three-phase systems of three or four conductors. This paper presents a new definition of instantaneous power that can be applied to all multiphase systems. Thus, the concept of tensor product is introduced to define the instantaneous power tensor and also the current decomposition in active and reactive components regardless of the number of phases of the power system. Finally, an exhaustive analysis of practical cases has been carried out at a simulation level which verified the proposed approach.

  5. Reactive power compensation a practical guide

    CERN Document Server

    Hofmann, Wolfgang; Just, Wolfgang

    2012-01-01

    The comprehensive resource on reactive power compensation, presenting the design, application and operation of reactive power equipment and installations The area of reactive power compensation is gaining increasing importance worldwide. If suitably designed, it is capable of improving voltage quality significantly, meaning that losses in equipment and power systems are reduced, the permissible loading of equipment can be increased, and the over-all stability of system operation improved. Ultimately, energy use and CO2 emisson are reduced. This unique guide discusses the

  6. Improved charge amplifier using hybrid hysteresis compensation

    Science.gov (United States)

    Amin-Shahidi, Darya; Trumper, David L.

    2013-08-01

    We present a novel charge amplifier, with a robust feedback circuit and a method for compensating piezoelectric actuator's hysteresis at low frequencies. The amplifier uses a modified feedback circuit which improves robustness to the addition of series load impedance such as in cabling. We also describe a hybrid hysteresis compensation method for enabling the charge amplifier to reduce hysteresis at low frequencies. Experimental results demonstrate the utility of the new amplifier design.

  7. 铁路简支梁桥竖向有载频率研究%study on vertical loaded frequencies of railway simply supported beam bridges

    Institute of Scientific and Technical Information of China (English)

    苏木标; 李建中; 梁志广

    2001-01-01

    The vertical loaded free frequencies for the different span simply supported beam bridges are investigated with the vehicle-bridge system model. The results show that these frequencies of the bridge are periodic changed in all the process in which a train moves on the bridge, and the values of the frequencies have the relation with not only the distribution of the stiffness and the mass of the bridge self, but also the stiffness of the spring and the mass under the spring for each wheel-set of the vehicles running on the bridge.%采用车-桥系统相互作用的计算模型,对不同跨度简支梁桥的竖向有载自振频率进行了深入研究。结果表明,桥梁的竖向有载自振频率在列车过桥全过程中是周期性变化的,其数值不仅与桥梁本身的刚度和质量分布有关,同时还与桥上车辆各轮对悬挂弹簧的刚度和簧下质量及其在桥上的位置有关。

  8. 深基环梁支护体系内力的研究%Loading of ring-beam support structure system in deep foundation ditch

    Institute of Scientific and Technical Information of China (English)

    丁克胜; 王沛; 杨宝珠

    2001-01-01

    Ring-beam support structure system is a new-type structure in deep foundation pit support structure.It may produre a hamonious load and gain a high bearing capacity.Its calculation model is elast ic multi-support.when using the saper 93 progvam with plane and overall calcula tion,the results are rather identical with the real condition,so it is a simple and effeetive method.%深基环梁支护体系是深基支护的一种新型结构,它受力均衡,承载力高,计算模型为多向弹性支座,利用Saper 93 程序进行平面整体设计计算的结果与实际比较相符,是一种非常简捷、有效的计算方法,但其水平支撑系统的内力受多方面因素的影响较大.

  9. Using optical feedback to compensate for the reflection loss caused by partially reflecting mirror in laser power beaming%反馈弥补激光能量传输中部分反射镜反射损失

    Institute of Scientific and Technical Information of China (English)

    黄虎; 李滨; 尤政; 王巍

    2013-01-01

    The photocell is usually covered by a layer of partially reflecting mirror in laser power beaming, which is used to reflect partial laser light, control the light power of receiver in real time and adjust the beam pointing from transmitter to receiver. The partially reflecting mirror will decrease the power transmission efficiency. In this paper a method of optical feedback laser power beaming is presented, the theoretical model is established and the laser output power expression is derived. The expression shows that the optical feedback can reduce the laser threshold current and increase the laser output power. The laser threshold currents and output powers in feedback and non feedback conditions were measured in experiments. The experiment results show that in optical feedback condition the threshold current is reduced by 25% and the output power is increased by 10% at the driving current of 60mA compared with those in non feedback condition. In the experiment, the output powers in the conditions with feedback and without reflecting mirror were also measured. The results show that the optical feedback can reduce the reflection loss caused by reflecting mirror from 10% to 3% . The optical feedback laser power transmission method compensates the reflection loss of the reflecting mirror and improves the power transmission efficiency.%激光能量传输中的光电池表面通常覆盖有一层部分反射镜,用于产生反射光信号,实时控制接收端的光功率大小以及调整发射端和接收端的对准度.部分反射镜会降低能量传输效率,提出了一种反馈式能量传输方式,建立了理论模型,推导了激光器输出功率表达式.从表达式中可以发现反馈激光可降低激光器的阈值电流,提高激光器的输出功率.通过实验测量了反馈和无反馈时激光器的阈值电流和输出功率,实验结果表明相比较于无反馈情况,反馈作用使激光器的阈值电流降低了25%,驱动电流为60 m

  10. Simulations of beam-beam and beam-wire interactions in RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung J.; Sen, Tanaji; /Fermilab; Abreu, Natalia P.; Fischer, Wolfram; /Brookhaven

    2009-02-01

    The beam-beam interaction is one of the dominant sources of emittance growth and luminosity lifetime deterioration. A current carrying wire has been proposed to compensate long-range beam-beam effects in the LHC and strong localized long-range beam-beam effects are experimentally investigated in the RHIC collider. Tune shift, beam transfer function, and beam loss rate are measured in dedicated experiments. In this paper, they report on simulations to study the effect of beam-wire interactions based on diffusive apertures, beam loss rates, and beam transfer function using a parallelized weak-strong beam simulation code (BBSIMC). The simulation results are compared with measurements performed in RHIC during 2007 and 2008.

  11. Design and implementation of adaptive slope compensation in current mode DC-DC converter

    Energy Technology Data Exchange (ETDEWEB)

    Guo Zhongjie; Wu Longsheng; Liu Youbao, E-mail: guozhongjie4213@126.com [Xi' an Microelectronic Technology Institute, Xi' an 710054 (China)

    2010-12-15

    To improve the compensation for the inherent instability in a current mode converter, the adaptive slope compensation, giving attention to the problems of the traditional compensation on compensation accuracy, loading capability and turning jitter, is presented. Based on the analysis of current loop, by detecting the input and output voltage, converting the adaptive slope compensation current, the compensation of the current loop is optimized successfully. It can not only improve the compensation accuracy but also eliminate the over compensation, the turning jitter and the poor loading capability in the reported slope compensation. A power supply chip with adaptive slope compensation has been fabricated in a 0.35 {mu}m CMOS process. The measurement results show that the chip starts up and operates steadily with the constant current limit under conditions of 5 V input voltage, from 10% to 100% duty cycle. (semiconductor integrated circuits)

  12. Essays in Executive Compensation

    NARCIS (Netherlands)

    D. Zhang (Dan)

    2012-01-01

    textabstractThis dissertation focuses on how executive compensation is designed and its implications for corporate finance and government regulations. Chapter 2 analyzes several proposals to restrict CEO compensation and calibrates two models of executive compensation that describe how firms would r

  13. Carbon Fiber Laminate Strengthened RC Beams Subjected to Fatigue Loading at Elevated Temperature%温度升高对碳纤维薄板增强RC梁疲劳性能的影响

    Institute of Scientific and Technical Information of China (English)

    周芝林; 黄培彦; 郭馨艳

    2008-01-01

    The static and fatigue tests under cyclic bending loads at different ambient temperatures of 20 ℃ and 80℃ are carried out to investigate the fatigue behavior of the reinforced concrete(RC) beams strengthened with'carbon fi-ber laminates(CFLs). The failure modes of the strengthened beams include CFLs debonded near the mid-span and steel rebar yielded or broken. S-N curves of strengthened beams are developed according to the test results. The fa-tigue limit, load versus deflection curves and strain response of strengthened beams are obtained as well. The results show that the fatigue behaviors of the strengthened beams are not significantly influenced by the ambient tempera-tures (lower than 80℃) when the fatigue load levels equal 25.0 kN, 27.5 kN and 30.0 kN.%为了研究碳纤维薄板增强钢筋混凝土梁在不同温度下的疲劳性能,分别在20℃和80℃的温度条件下对26根增强梁进行了三点弯曲静载和疲劳试验.结果表明:当疲劳载荷水平为25.0 kN,27.5 kN和30.0 kN时,试件的S-N曲线、疲劳极限、破坏模式、挠度曲线和应变反映受环境温度的影响较小.

  14. Moment Contribution Capacity of Tendon Prestressed Partial on Concrete Beam-column Joint Interior According to Provisions ACI 318-2008 Chapter 21.5.2.5(c Due to Cyclic Lateral Loads

    Directory of Open Access Journals (Sweden)

    Astawa Made Dharma

    2016-01-01

    Full Text Available This research designed a partial prestressed concrete beam-column with reinforced concrete interior joint, using square columns of 400/400 mm, reinforcement 6 D16 + 4D13, section beam 250/400 mm, tensile reinforcement 5 D13, compression reinforcement 3 D13 + 2 strand tendon D12,7 mm , and joint without plastic hinge, then tested in laboratory with lateral cyclic loads on peak column, static axial load 1120 kN on the centre column, to get the tendon capacity to assume positive and negative bending moments due to lateral load, according to provisions of ACI 318-2008 part 21.5.2.5 (c. Test results showed that the moment tendon contribution on beam section, in the tensile area, the positive and negative moment both on the left side or the right side column are all qualified ( 25 %. As for the negative moment, either left or right side column are all qualified (4.0. Although the contribution of positive moment capacity tendon in compression areas does not qualify, in overall, the reliability and ductility of the structure qualify.

  15. 静载作用下的预应力空心板单梁受力试验分析%The analysis of prestressed concrete hollow slab beam under the static test load

    Institute of Scientific and Technical Information of China (English)

    郭东升; 贾艳敏; 陶永靖

    2014-01-01

    Based on an actual bridge as the project background,did the hollow slab single static test,establishing the finite element model of hol-low plate beam by Midas Civil,simulation of single beam static loading process,analysis of deflection and stress of the beam,the results show that the hollow plate beam’s deflection meet design and use requirements,the stress state was reasonable,the stress variation along the beam high linear under the static test load,structure is safe.%以实桥为工程依托,进行了空心板单梁试验,并应用Midas Civil有限元软件建立空心板单梁模型,模拟单梁静力加载过程,对比分析空心板梁挠度及控制截面应力,结果表明:空心板梁在试验静力荷载作用下,挠度满足设计使用要求,应力状态合理,沿梁高线性变化,空心板梁受力安全。

  16. Beam-beam simulation code BBSIM for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung J.; Sen, Tanaji; /Fermilab

    2011-01-01

    A highly efficient, fully parallelized, six-dimensional tracking model for simulating interactions of colliding hadron beams in high energy ring colliders and simulating schemes for mitigating their effects is described. The model uses the weak-strong approximation for calculating the head-on interactions when the test beam has lower intensity than the other beam, a look-up table for the efficient calculation of long-range beam-beam forces, and a self-consistent Poisson solver when both beams have comparable intensities. A performance test of the model in a parallel environment is presented. The code is used to calculate beam emittance and beam loss in the Tevatron at Fermilab and compared with measurements. They also present results from the studies of stwo schemes proposed to compensate the beam-beam interactions: (a) the compensation of long-range interactions in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven and the Large Hadron Collider (LHC) at CERN with a current carrying wire, (b) the use of a low energy electron beam to compensate the head-on interactions in RHIC.

  17. Friction Effects on Inertia Compensators used for Heliostat Base Motion Isolation.

    Science.gov (United States)

    The base motion isolation of an optical beam deflector with a two-axis gimbal support ( heliostat ) is discussed. The use of an auxiliary inertia...coupled between the elevation gimbal and the heliostat mirror to produce a compensating torque referred to as a gear compensator and a belt compensator

  18. DEFORMATION BEHAVIOR OF STEEL FIBER REINFORCED CONCRETE BEAMS WITH BASALT FRP BARS UNDER REPEATED LOAD AFTER SUSTAINED LOADING%长期持荷后玄武岩纤维增强聚合物筋钢纤维高强混凝土梁在重复荷载下的变形性能

    Institute of Scientific and Technical Information of China (English)

    韩全吉; 王守恒; 朱海堂; 高丹盈; 崔海波

    2014-01-01

    为了研究经历长期持荷后的玄武岩纤维增强聚合物( BFRP)筋钢纤维高强混凝土梁在重复荷载作用下的变形性能,进行了7根BFRP筋钢纤维高强混凝土梁的受弯试验,分析BFRP筋配筋率、钢纤维体积率以及加载水平等因素对梁的变形性能的影响。结果表明:经过10次卸载、加载循环后,受力BFRP筋与混凝土之间的黏结性能没有发生退化;荷载水平、钢纤维掺量及BFRP筋配筋率对BFRP筋钢纤维高强混凝土梁的加载-卸载挠度曲线及挠度恢复能力有不同程度的影响;BFRP筋钢纤维高强混凝土梁具有较高的变形恢复能力和良好的抗重复荷载性能。%In order to study the deformation performance of steel fiber reinforced high-strength concrete beams with BFRP rebars, the bending test of 7 beams under repeated load after suffering long-term sustaining load were carried out.The effects of reinforcement ratio of BFRP bars , fraction of steel fiber by volume and loading level on deformation performance of beams were analyzed .The results shown that the bonding behavior between BFRP rebars and concrete is not degradative after 10 loading-unloading cycles;the factors,including loading level , the dosage of steel fiber and the reinforcement ratio of BFRP , express the different levels of influence on the load-deflection curve and the deflection recovery capability of test beams;and steel fiber reinforced high-strength concrete beams with BFRP rebars possess higher deflection recovery capability and better repeated load resistance .

  19. Harmonic currents Compensator Grid-Connected Inverter at the Microgrid

    DEFF Research Database (Denmark)

    Asuhaimi Mohd Zin, A.; Naderipour, A.; Habibuddin, M.H.

    2016-01-01

    The main challenge associated with the grid-connected inverter in distributed generation (DG) systems is to maintain the harmonic contents in output current below the specified values and compensates for unbalanced loads even when the grid is subject to disturbances such as harmonic distortion...... and unbalanced loads. To overcome these challenges, a current control strategy for a three-phase grid-connected inverter under unbalanced and nonlinear load conditions is presented. It enables grid-connected inverter by the proposed control method to inject balanced clean currents to the grid even when the local...... loads are unbalanced and/or nonlinear and also compensate of the harmonic currents and control the active and reactive power. The main advantage and objective of this method is to effectively compensate for the harmonic currents content of the grid current and microgrid without using any compensation...

  20. Holographic motion picture camera with Doppler shift compensation

    Science.gov (United States)

    Kurtz, R. L. (Inventor)

    1976-01-01

    A holographic motion picture camera is reported for producing three dimensional images by employing an elliptical optical system. There is provided in one of the beam paths (the object or reference beam path) a motion compensator which enables the camera to photograph faster moving objects.

  1. Rationalizing vaccine injury compensation.

    Science.gov (United States)

    Mello, Michelle M

    2008-01-01

    Legislation recently adopted by the United States Congress provides producers of pandemic vaccines with near-total immunity from civil lawsuits without making individuals injured by those vaccines eligible for compensation through the Vaccine Injury Compensation Program. The unusual decision not to provide an alternative mechanism for compensation is indicative of a broader problem of inconsistency in the American approach to vaccine-injury compensation policy. Compensation policies have tended to reflect political pressures and economic considerations more than any cognizable set of principles. This article identifies a set of ethical principles bearing on the circumstances in which vaccine injuries should be compensated, both inside and outside public health emergencies. A series of possible bases for compensation rules, some grounded in utilitarianism and some nonconsequentialist, are discussed and evaluated. Principles of fairness and reasonableness are found to constitute the strongest bases. An ethically defensible compensation policy grounded in these principles would make a compensation fund available to all individuals with severe injuries and to individuals with less-severe injuries whenever the vaccination was required by law or professional duty.

  2. 三峡升船机横梁贝雷架支撑系统荷载试验%Support system load test of beam Bailey truss of Three Gorges Project ship lift

    Institute of Scientific and Technical Information of China (English)

    汪文亮; 肖传勇; 张俊霞

    2013-01-01

    During the continued construction of Three Gorges Project ship lift,the loading test experi-ment has been carried out before the pouring work of the beam concrete,which is aimed at the complex charac-teristics of the bracing system of tower column beam construction. The experiment chose axle 1 beam,axle 2 beam and corresponding foundation beams’Bailey trusses as models,and the loading prototype test is conduct-ed according to 1∶1 ratio scale. Through arranging proper monitoring points and adopting reasonable testing fre-quency,the experiment completed the collection and analyzing of test data. The test results are as follows:The test obtaines the maximum stress of different member bars during the loading procedure. With the increasing of loading capacity,the bending variation of beams and Bailey trusses build up slowly,while altitudes of form-work and framed bent drop. With the increasing of loading capacity,the beams and foundation Bailey trusses ex-perienced subtle side movements. The variation of both the axle 2 beam formwork and the framed bent’s vertical-ity from left to right is very tiny. The monitoring data indicates that,the parameters of strengthened Bailey truss-es meet the safety requirements,and the proposal applies to the tower column beam construction while ensuring its safety.%在三峡升船机续建工程中,针对塔柱横梁施工支撑体系复杂的特点,在横梁混凝土浇筑前进行荷载试验。试验选取轴1、轴2横梁及其相应的基础梁贝雷架作为模型,按照1∶1进行荷载原型试验,通过布置监测点以及采用合理的检测频率,完成试验数据的采集与分析。本次试验取得以下成果:得出了各类型杆件在加载过程中的最大应力值;随着加载量的增加,横梁、基础梁贝雷架的挠度变化量慢慢增大,模板及排架立杆高程在下降;随着加载量的增加,横梁、基础梁贝雷架都发生了较小的侧向位移,轴2横梁模板

  3. Beam-beam observations in the Relativistic Heavy Ion Collider

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Y. [Brookhaven National Laboratory (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Laboratory (BNL), Upton, NY (United States); White, S. [Brookhaven National Laboratory (BNL), Upton, NY (United States)

    2015-06-24

    The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been operating since 2000. Over the past decade, thanks to the continuously increased bunch intensity and reduced β*s at the interaction points, the maximum peak luminosity in the polarized proton operation has been increased by more than two orders of magnitude. In this article, we first present the beam-beam observations in the previous RHIC polarized proton runs. Then we analyze the mechanisms for the beam loss and emittance growth in the presence of beam-beam interaction. The operational challenges and limitations imposed by beam-beam interaction and their remedies are also presented. In the end, we briefly introduce head-on beam-beam compensation with electron lenses in RHIC.

  4. Experimental Study on Load Test of Concrete Simply Supported T-beam Bridge Reinforced by CFRP in Service%CFRP加固在役混凝土简支T梁实桥荷载试验研究

    Institute of Scientific and Technical Information of China (English)

    周勇超; 郝宪武

    2012-01-01

    Based on load test of concrete simply supported T-beam bridge reinforced by CFRP in service, the cross-section stress and stiffness in serviceability stage are analyzed in this paper. The results show that CFRP can be coordination with concrete and the carrying capacity of concrete simply supported T-beam is increased by about 45.3% , the stiffness is increased by about 52.7%. Considering the second force, the calculation methods of cross-section stress and stiffness of T-beam in serviceability stage are derived, the calculations are consistent with load test results.%通过对利用CFRP加固的在役钢筋混凝土简支T梁桥荷载试验,研究了正常使用状态下的截面应力、刚度,证明CFRP能够与混凝土协调工作,对在役混凝土简支T梁的承载力提高幅度约为45.3%,刚度提高幅度约为52.7%.在考虑二次受力的基础上,推导了在正常使用状态下,CFRP加固混凝土简支T梁截面应力、短期刚度的计算方法,计算结果与实测结果吻合良好.

  5. Cooperation, compensation and transition

    NARCIS (Netherlands)

    Ju, Y.

    2004-01-01

    Cooperation and compensation are two important and well-linked issues in economics. The central question in cooperation is how to share the joint gains among participating players. Compensation is a specific aspect of surplus sharing problems providing incentives for agents to sacrifice their own di

  6. Options in Compensation

    DEFF Research Database (Denmark)

    Flor, Christian Riis; Frimor, Hans; Munk, Claus

    2014-01-01

    We derive the optimal compensation contract in a principal–agent setting in which outcome is used to provide incentives for both effort and risky investments. To motivate investment, optimal compensation entails rewards for high as well as low outcomes, and it is increasing at the mean outcome to...

  7. Voltage holding study of 1 MeV accelerator for ITER neutral beam injector.

    Science.gov (United States)

    Taniguchi, M; Kashiwagi, M; Umeda, N; Dairaku, M; Takemoto, J; Tobari, H; Tsuchida, K; Yamanaka, H; Watanabe, K; Kojima, A; Hanada, M; Sakamoto, K; Inoue, T

    2012-02-01

    Voltage holding test on MeV accelerator indicated that sustainable voltage was a half of that of ideal quasi-Rogowski electrode. It was suggested that the emission of the clumps is enhanced by a local electric field concentration, which leads to discharge initiation at lower voltage. To reduce the electric field concentration in the MeV accelerator, gaps between the grid supports were expanded and curvature radii at the support corners were increased. After the modifications, the accelerator succeeded in sustaining -1 MV in vacuum without beam acceleration. However, the beam energy was still limited at a level of 900 keV with a beam current density of 150 A∕m(2) (346 mA) where the 3 × 5 apertures were used. Measurement of the beam profile revealed that deflection of the H(-) ions was large and a part of the H(-) ions was intercepted at the acceleration grid. This causes high heat load on the grids and the breakdowns during beam acceleration. To suppress the direct interception, new grid system was designed with proper aperture displacement based on a 3D beam trajectory analysis. As the result, the beam deflection was compensated and the voltage holding during the beam acceleration was improved. Beam parameter of the MeV accelerator was increased to 980 keV, 185 A∕m(2) (427 mA), which is close to the requirement of ITER accelerator (1 MeV, 200 A∕m(2)).

  8. Hybrid compensation arrangement in dispersed generation systems

    DEFF Research Database (Denmark)

    Chen, Zhe; Blaabjerg, Frede; Pedersen, John Kim

    2005-01-01

    This paper presents a hybrid compensation system consisting of an active filter and distributed passive filters. In the system, each individual passive filter is connected to a distortion source and designed to eliminate main harmonics and supply reactive power for the distortion source, while...... are performed for a power system including the dispersed generation units connected into the system through power electronic converters and diode rectifier loads, which produce the distorted waveforms. The simulation results have demonstrated that good compensation effects can be achieved by using the combined...

  9. Climate change and compensation

    DEFF Research Database (Denmark)

    Jensen, Karsten Klint; Flanagan, Tine Bech

    2013-01-01

    This paper presents a case for compensation of actual harm from climate change in the poorest countries. First, it is shown that climate change threatens to reverse the fight to eradicate poverty. Secondly, it is shown how the problems raised in the literature for compensation to some extent...... are based on misconceptions and do not apply to compensation of present actual harm. Finally, two arguments are presented to the effect that, in so far as developed countries accept a major commitment to mitigate climate change, they should also accept a commitment to address or compensate actual harm from...... in the future, then there is also moral reason to address these harms if they materialize now. We argue that these principles are applicable to climate change, and that given the commitment of wealthy countries to a "common but differentiated responsibility," they lead to a commitment to address or compensate...

  10. 电-热-力载下 BNNTs 增强压电梁的屈曲分析%Buckling analysis of piezoelectric beam reinforced with BNNTs under electro-thermo-mechanical loadings

    Institute of Scientific and Technical Information of China (English)

    杨金花; 张鹏君

    2015-01-01

    By employing linear strain and utilizing piezoelectric theory including thermal effects,the constitutive relations of the piezoelectric beam reinforced with BNNTs are es-tablished.The buckling governing equations of the structure are derived through variational principle.In numerical examples,the effects of voltage,temperature,boundary condition and volume fraction on the buckling load of piezoelectric beam reinforced with BNNTs are discussed in detail.The following conclusions may be drawn from the present work:apply-ing negative and positive voltage to BNNT leads to increase and decrease of the buckling load.The buckling load of piezoelectric beam reinforced with BNNTs increases with the de-crease of temperature,and also increases when the volume fraction of BNNT in matrix in-creases.%运用线性应变几何关系及考虑温度效应的压电理论,建立了 BNNTs 增强压电梁的本构关系,通过变分推导出了结构的屈曲控制方程。算例中详细讨论了电压、温度、边界条件及体积比对 BNNTs 增强压电梁屈曲载荷的影响。研究结果表明,在 BNNTs 两端施加负或正电压可使压电梁的屈曲载荷增加或减小;BNNTs 增强压电梁的屈曲载荷随着温度的降低以及硼氮纳米管所占体积比的增加而增大。

  11. SEMICONDUCTOR INTEGRATED CIRCUITS Design and implementation of adaptive slope compensation in current mode DC—DC converter

    Science.gov (United States)

    Zhongjie, Guo; Longsheng, Wu; Youbao, Liu

    2010-12-01

    To improve the compensation for the inherent instability in a current mode converter, the adaptive slope compensation, giving attention to the problems of the traditional compensation on compensation accuracy, loading capability and turning jitter, is presented. Based on the analysis of current loop, by detecting the input and output voltage, converting the adaptive slope compensation current, the compensation of the current loop is optimized successfully. It can not only improve the compensation accuracy but also eliminate the over compensation, the turning jitter and the poor loading capability in the reported slope compensation. A power supply chip with adaptive slope compensation has been fabricated in a 0.35 μm CMOS process. The measurement results show that the chip starts up and operates steadily with the constant current limit under conditions of 5 V input voltage, from 10% to 100% duty cycle.

  12. 1年持续载荷下GFRP-混凝土组合梁长期性能试验%Long-term property test of GFRP-concrete composite beam under sustained load for one year

    Institute of Scientific and Technical Information of China (English)

    薛伟辰; 张士前; 梁智殷

    2016-01-01

    玻璃纤维增强树脂(GFRP)-混凝土组合梁由上部混凝土板和下部 GFRP型材以及连接二者的抗剪连接件组成。开展了2根 GFRP-混凝土组合梁(非预应力及施加体外预应力组合梁各1根)在1年持续载荷下行为的试验研究。考虑混凝土收缩徐变及 GFRP型材蠕变耦合的影响,开展了50年的24根 GFRP-混凝土组合梁时随有限元参数分析。结果表明:在1年持续载荷下,非预应力与施加体外预应力组合梁长期挠度分别为其初始挠度的1.42倍及2.91倍;非预应力与预应力组合梁中连接件的长期滑移分别为0.230 mm及0.164 mm,相比初始滑移2种组合梁的最终滑移分别增加了53.3%和58.2%;50年后,非预应力组合梁长期挠度与初始挠度的比值在1.50~1.56之间;而施加体外预应力组合梁长期挠度与初始挠度的比值在3.03~6.08之间。基于以上研究提出了 GFRP-混凝土组合梁长期挠度的计算建议。%The glass fiber reinforced plastic (GFRP)-concrete composite beam consists of a concrete slab on the upper side,a GFRP profile on the lower side and shear connectors to connect these two sides.A test study was con-ducted on the behaviors of two GFRP-concrete composite beams (non-prestressed and external prestressed composite beams each had one)under sustained load for one year.A time-dependent finite element parametric analysis of 24 GFRP-concrete composite beams,taking coupling effect of the shrinkage and creep of concrete and creep of GFRP profile into account,was carried out for 50 years.The results show that long-term deflections of the non-prestressed and external prestressed composite beams are 1.42 and 2.91 times of their respective instantaneous deflections under sustained load for one year.The long-term slips of the non-prestressed and external prestressed composite beams are 0.230 mm and 0.164 mm,respectively.Compared with initial slips,the terminal slips of the two composite beams increase by 53

  13. Electronic compensation technique to deliver a total body dose

    Science.gov (United States)

    Lakeman, Tara E.

    Purpose: Total body irradiation (TBI) uses large parallel-opposed radiation fields to suppress the patient's immune system and eradicate the residual cancer cells in preparation of recipient for bone marrow transplant. The manual placement of lead compensators has been conventionally used to compensate for the varying thickness throughout the body in large-field TBI. The goal of this study is to pursue utilizing the modern electronic compensation technique to more accurately and efficiently deliver dose to patients in need of TBI. Method: Treatment plans utilizing the electronic compensation to deliver a total body dose were created retrospectively for patients for whom CT data had been previously acquired. Each treatment plan includes two pair of parallel opposed fields. One pair of large fields is used to encompass the majority of the patient's anatomy. The other pair are very small open fields focused only on the thin bottom portion of the patient's anatomy, which requires much less radiation than the rest of the body to reach 100% of the prescribed dose. A desirable fluence pattern was manually painted within each of the larger fields for each patient to provide a more uniform distribution. Results: Dose-volume histograms (DVH) were calculated for evaluating the electronic compensation technique. In the electronically compensated plans, the maximum body doses calculated from the DVH were reduced from the conventionally-compensated plans by an average of 15%, indicating a more uniform dose. The mean body doses calculated from the electronically compensated DVH remained comparable to that of the conventionally-compensated plans, indicating an accurate delivery of the prescription dose using electronic compensation. All calculated monitor units were within clinically acceptable limits. Conclusion: Electronic compensation technique for TBI will not increase the beam on time beyond clinically acceptable limits while it can substantially reduce the compensator setup

  14. Adaptive Compensation of Reactive Power With Shunt Active Power Filters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Asiminoaei, Lucian; Hansen, Steffan;

    2008-01-01

    This paper describes an adaptive method for compensating the reactive power with an active power filter (APF), which is initially rated for mitigation of only the harmonic currents given by a nonlinear industrial load. It is proven that, if the harmonic currents do not load the APF at the rated...

  15. CLIC Drive Beam Accelerating Structures

    CERN Document Server

    Wegner, Rolf

    2012-01-01

    Travelling structures for accelerating the high-current (4.2 A) CLIC Drive Beam to an energy of 2.37 GeV are presented. The structures are optimised for efficiency (full beam loading operation) and a desired filling time. Higher order modes are studied and are reduced by detuning along the structure and by damping with silicon carbide loads.

  16. FINITE ELEMENT ANALYSIS OF FAILURE MODES OF BLAST-LOADED R/C BEAMS%爆炸荷载作用下钢筋混凝土梁破坏形态有限元分析

    Institute of Scientific and Technical Information of China (English)

    方秦; 柳锦春; 张亚栋; 钱七虎

    2001-01-01

    The flexural failure mode of R/C frames or beams is usually observed in case of blast loads with long duration. However, shear failure mode may occur before the flexural failure takes place in case of blast loads with short duration such as impulsive loadings induced by chemical explosion. This phenomenon is observed in both laboratory and in-situ tests. The reason is that the impulsive loading excites the shear force in the component of the structures and causes the structures fail in the manner of shear failure. Based on Timoshenko beam theory, a non-linear layered beam element is proposed in this paper to investigate the response and failure modes of blast-loaded R/C beams. Non-linear material properties, strain-rate effects of concrete and steel are taken into account in the material models. The dynamic responses and various failure modes, including flexure, flexure-shear and shear of the blast-loaded R/C beams are predicted. A good agreement between the numerical results and experimental results is reached.%在持续时间较长的爆炸荷载作用下,钢筋混凝土框架或梁通常会发生常见的弯曲破坏形态,但是在持续时间较短的爆炸荷载,如化学爆炸产生的脉冲荷载作用下,钢筋混凝土结构有可能在弯曲破坏发生之前产生剪切破坏。这种现象已被室内外试验所证实,其原因是脉冲荷载激发了结构中的剪力,从而使结构产生剪切破坏。为了预报钢筋混凝土梁在爆炸荷载下的响应和破坏形态,本文提出了一种基于Timoshenko梁理论的非线性分层梁有限元法。在材料模型中考虑了混凝土和钢筋的非线性和应变速率效应等因素。应用这方法,本文计算分析了爆炸荷载作用下钢筋混凝土梁的动态响应以及弯曲、弯剪和剪切等不同的破坏形态,计算预报的结构动态响应和破坏形态与现场试验结果有较好的一致性。

  17. A Compensated Predict Current Strategy for Single-sided Linear Induction Motors Considering Dynamical Eddy-effects and Load Vibrations%考虑动态端部效应与负载扰动的单边直线感应电机预测电流补偿控制

    Institute of Scientific and Technical Information of China (English)

    邓江明; 陈特放; 唐建湘; 彭鹏; 居平

    2015-01-01

    论文提出一种针对单边直线感应电机(single-sided linear induction motors,SLIMs)的基于非线性负载扰动观测器的预测电流补偿控制策略。首先考虑到SLIM特有的动态端部效应的影响,通过跟踪补偿 M-轴电流分量来维持次级磁链 T-轴分量的恒定,而后在一次线性条件下,引入一阶离散泰勒级数对速度状态进行预测。另一方面将电机气隙变化与各类边端效应对电机推力输出的影响统一为系统受到负载扰动的影响,而应对此扰动,通过非线性扰动观测器,在预测前向控制通路增加了实时补偿控制量,借此提升整个预测控制系统的鲁棒特性。最后实验对所提算法的有效性进行了验证。%This paper presented a predictive current compensation control for a single-sided linear induction motor (SLIM)with nonlinear disturbance observers (NDOB). Firstly, to maintainT-axes secondary component flux linkage constant with consideration of the special dynamical eddy-effects (DEE) of the SLIM, a instantaneously tracing compensation ofM-axes current components was analyzed. Secondly, a predictive current scheme based on Taylor-discretization algorithm for promoting speed dynamical response and minimizing speed stable ripple was proposed. Finally, to deal with the external load coupled uncertainties and measured errors of unavoidable feedback control variables, i.e., current and speed, an effective kind of nonlinear disturbance observer was employed to estimate and feed forward compensate these load vibrations, so the robustness of the control system could be guaranteed. Experimental verification of the feasibility of the proposed predictive current compensation for a SLIM control system is performed.

  18. A Novel Wireless and Temperature-Compensated SAW Vibration Sensor

    OpenAIRE

    Wen Wang; Xufeng Xue; Yangqing Huang; Xinlu Liu

    2014-01-01

    A novel wireless and passive surface acoustic wave (SAW) based temperature-compensated vibration sensor utilizing a flexible Y-cut quartz cantilever beam with a relatively substantial proof mass and two one-port resonators is developed. One resonator acts as the sensing device adjacent to the clamped end for maximum strain sensitivity, and the other one is used as the reference located on clamped end for temperature compensation for vibration sensor through the differential approach. Vibrati...

  19. Workers Compensation Claim Data -

    Data.gov (United States)

    Department of Transportation — This data set contains DOT employee workers compensation claim data for current and past DOT employees. Types of data include claim data consisting of PII data (SSN,...

  20. Climate change and compensation

    DEFF Research Database (Denmark)

    Jensen, Karsten Klint; Flanagan, Tine Bech

    2013-01-01

    This paper presents a case for compensation of actual harm from climate change in the poorest countries. First, it is shown that climate change threatens to reverse the fight to eradicate poverty. Secondly, it is shown how the problems raised in the literature for compensation to some extent...... are based on misconceptions and do not apply to compensation of present actual harm. Finally, two arguments are presented to the effect that, in so far as developed countries accept a major commitment to mitigate climate change, they should also accept a commitment to address or compensate actual harm from...... climate change. The first argument appeals to the principle that if it is an injustice to cause risk of incurring harm in the future, then it is also an injustice to cause a similar harm now. The second argument appeals to the principle that if there is moral reason to reduce the risk of specific harms...

  1. Linear Optics Compensation of the Superconducting Wiggler in HLS

    CERN Document Server

    Wang, Lin; Li, Wei-min; Xu, Hong-liang; Zhang, He

    2005-01-01

    Hefei Light Source is a dedicated VUV light source. A superconducting wiggler magnet with 6 Tesla magnetic field was installed on the storage ring to generate hard X-ray radiation. With the compensation of tune shift due to insertion device, beam was successfully stored, but the beam lifetime was decreased much. In order to cure the lifetime, a simple hard-edge model of the wiggler was constructed in lattice simulation code and the compensation scheme was extensively studied again. Calculation showed that it is difficulty to localize the strong focusing effects from wiggler magnet. Then, a new scheme was brought forward and experimental result showed that it can restore the beam lifetime largely. As the application of LOCO method in HLS, a new compensation scheme was calculated by response matrix fitting, and the experimental result also presented in this paper.

  2. Robotic motion compensation for applications in radiation oncology

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, Christian

    2013-07-22

    Radiation therapy today, on account of improvements in treatment procedures over the last 60 years, allows precise treatment of static tumors inside the human body. However, irradiation of moving tumors is still a challenging task as moving tumors often leave the treatment beam and the radiation dose delivered to the tumor reduces simultaneously increasing that on healthy tissue. This research work aims to push the frontiers of radiation therapy in order to enable precise treatment of moving tumors with focus on research and development of a unique real-time system enabling active motion compensation through robotic means to compensate tumor motion. During treatment, patients lie on a treatment couch which is normally used for static position corrections of patient set-up errors prior to radiation treatment. The treatment couch used, called HexaPOD, is a parallel manipulator with six degrees of freedom which can precisely position heavy loads inside a small region. Despite the HexaPOD not initially built with dynamics in mind, it is used in this work for sustained motion compensation by moving patients such that tumors stay precisely located at the center of the treatment beam during the complete course of treatment. In order to realize real-time tumor motion compensation by means of the HexaPOD, several challenges need to be addressed. Real-time aspects are covered by the adoption of a hard real-time operation system in combination with measurement and estimation of latencies of all physical quantities in the compensation system such as tumor or breathing position measurements. Accurate timing information is respected consistently in the whole system and all software-induced latencies are adaptively compensated for. This requires knowledge of future tumor positions from predictors. Several predictors for breathing and tumor motion predictions are proposed and evaluated in terms of a variety of different performance metrics. Extensions to prediction algorithms are

  3. Numerical analysis of parasitic crossing compensation with wires in DA$\\Phi$NE

    CERN Document Server

    Valishev, A; Milardi, C; Zobov, M

    2015-01-01

    Current bearing wire compensators were successfully used in the 2005-2006 run of the DA{\\Phi}NE collider to mitigate the detrimental effects of parasitic beam-beam interactions. A marked improvement of the positron beam lifetime was observed in machine operation with the KLOE detector. In view of the possible application of wire beam-beam compensators for the High Luminosity LHC upgrade, we revisit the DA{\\Phi}NE experiments. We use an improved model of the accelerator with the goal to validate the modern simulation tools and provide valuable input for the LHC upgrade project.

  4. Numerical Analysis of Parasitic Crossing Compensation with Wires in DA$\\Phi$NE

    Energy Technology Data Exchange (ETDEWEB)

    Valishev, A. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Shatilov, D. [Russian Academy of Sciences (RAS), Novosibirsk (Russian Federation). Budker Inst. of Nuclear Physics (BINP); Milardi, C. [National Inst. of Nuclear Physics (INFN), Frascati (Italy). National Lab. of Frascati (INFN-LNF); Zobov, M. [National Inst. of Nuclear Physics (INFN), Frascati (Italy). National Lab. of Frascati (INFN-LNF)

    2015-06-24

    Current-bearing wire compensators were successfully used in the 2005-2006 run of the DAΦNE collider to mitigate the detrimental effects of parasitic beam-beam interactions. A marked improvement of the positron beam lifetime was observed in machine operation with the KLOE detector. In view of the possible application of wire beam-beam compensators for the High Luminosity LHC upgrade, we revisit the DAΦNE experiments. We use an improved model of the accelerator with the goal to validate the modern simulation tools and provide valuable input for the LHC upgrade project.

  5. ACTS Rain Fade Compensation

    Science.gov (United States)

    Coney, Thom A.

    1996-01-01

    Performance status of the Adaptive Rain Fade Compensation includes: (1) The rain fade protocol is functional detecting fades, providing an additional 10 dB of margin and seamless transitions to and from coded operation; (2) The stabilization of the link margins and the optimization of rain fade decision thresholds has resulted in improved BER performance; (3) Characterization of the fade compensation algorithm is ongoing.

  6. Dosage compensation in birds

    OpenAIRE

    McQueen, H A; McBride, D; Miele, G; Bird, A.P.; Clinton, M

    2001-01-01

    The Z and W sex chromosomes of birds have evolved independently from the mammalian X and Y chromosomes [1]. Unlike mammals, female birds are heterogametic (ZW), while males are homogametic (ZZ). Therefore male birds, like female mammals, carry a double dose of sex-linked genes relative to the other sex. Other animals with nonhomologous sex chromosomes possess "dosage compensation" systems to equalize the expression of sex-linked genes. Dosage compensation occurs in animals as diverse as mamma...

  7. Fast method of the identification of dynamic load location on the beam%梁结构上动载荷位置识别的快速算法

    Institute of Scientific and Technical Information of China (English)

    张景; 张方; 姜金辉; 蒋祺

    2016-01-01

    This paper used a simply supported beam as a study objective ,and set up the finite element model of the beam by PATRAN to obtain the simulating displacement response of the beam .The code was written in MATLAB to identify the location of the dynamic load acting on the beam .This paper proposed a fast method based on the minimum discrimi‐nate coefficient method ,and it identified the the location of the dynamic load by the way of gradually approach .Com‐pared with the common method ,this method cut back the calculation process and time by reduce the division of the finite elements .Simulation showed that this fast method reduced the time of calculation with ensuring the accuracy and exact‐ness of the identification ,which brought convenience to the work of identifying dynamic loads .%将简支梁作为研究对象,通过PATRAN软件建立梁的有限元模型,仿真计算出梁的位移响应,再利用MATLAB编写算法,识别出作用在梁上的动载荷的位置。在最小判别系数法的基础上提出了一种快速算法,该算法通过逐步逼近的方式来识别动载荷的作用位置。与常规方法相比,该快速算法减少了有限单元的划分,所以有效地减少了计算过程并且缩短了计算时间。通过仿真计算,验证了这一快速算法在保证了识别精度和准确性的前提下,缩短了计算时间,为动载荷识别工作带来了便利。

  8. 轨道交通先张法预制U型梁静载试验研究%Static Load Test of Pre-tensioned Pre-casted U-Beam in Rail transit

    Institute of Scientific and Technical Information of China (English)

    谭程龙; 宋郁民; 沈哲亮

    2016-01-01

    静载试验是检验桥梁整体受力性能、桥梁设计和施工质量是否满足设计和规范要求的主要方法,也是竣工验收的必要过程。静载试验结果为确定或评定桥梁运营荷载等级最直接且最有效的办法。以青岛 R13线轨道交通先张法预制 U 型梁为例,按照一定抽样频率对成批预制的先张法 U 型梁,进行静载试验,测试 U 型梁在试验荷载下的刚度、应力及裂缝宽度,分析试验结果,该先张法 U 型梁的力学性能均满足规范要求,为今后先张法预制 U 型梁推广使用提供一定的参考。%Bridge’s static load test is an important means of inspecting its overall mechanical performance ,and is also effective measure to check its quality ,and also is a necessary process of its completion and acceptance .At the same time ,the results is the most direct and effective way to assess bridge load grade operations .This research taken the pre- tensioned pre-casted U shaped beam in Qingdao rail transport as an example ,static load tests were carried out for parts of pre-tensioned pre-casted U-beam according to a certain proportion .The mechanical properties of U-beam were analyzed and assessed according to rigidity ,stresses and crack width ,all experimental results could meet the relevant specifica-tions ,and can promote the use of pre-tensioned pre-casted U-beam in the future .

  9. 直线加速器驻波腔中的瞬态束流负载效应%Transient Beam Loading Effects in Standing Wave Cavities of Linear Accelerators

    Institute of Scientific and Technical Information of China (English)

    裴士伦; 王书鸿

    2006-01-01

    在高能加速器中,随着单个束团和束团串中电荷量的提高,当粒子束穿过加速腔的时候,感应出的瞬态束流负载电压也越来越高.但是,在通常分析束流负载的时候,往往对稳态束流负载研究的比较多,而对瞬态束流负载的研究要相对少一些.本文首先对束流负载的瞬态特性和束团穿过加速腔时高频源所看到谐振腔谐振频率的变化方式进行了分析,然后又对两种情况下谐振腔的最优失谐条件进行了讨论,并给出了相应的解析公式.在第1种情况下,当粒子束穿过加速腔的时候,谐振腔的自然谐振频率能够及时地得到调节,从而使高频源的电流与谐振腔的腔压同相,以提高高频源的效率;在第2种情况下,当粒子束穿过加速腔的时候,谐振腔的自然谐振频率保持不变,不能被调节.最后,还对BEPCⅡ现有预注入器的预聚束腔、BEPCⅡ未来预注入器的两个次谐波聚束腔中的瞬态束流负载效应进行了分析.%In modern high energy accelerators, with the increase of charge in a bunch or a bunch train,the induced transient beam loading voltages become higher and higher when the beams pass through the standing wave cavities. But in the usual analysis, people usually pay more attention to the steady state instead of the transient state beam loading. In this paper, the transient nature of beam loading and the cavity's frequency changing behavior seen by the RF power generator are studied, and then the optimum detuning conditions in two cases are derived. In the first case, the resonant cavity's frequency can be tuned to meet the in-phase condition between the RF power generator current and the cavity voltage during the passage of beams. While in the second case, only few bunches in the bunch train and the cavity's resonant frequency is fixed during the passage of the bunch train. At last, the beam loading effects in the prebuncher of BEPC Ⅱ pre-injector and the two SHBs of

  10. 竖向集中荷载作用下体外预应力混凝土连续梁解析解%Vertical Concentrated Load Externally Prestressed Concrete Continuous Beam Analytical Solution

    Institute of Scientific and Technical Information of China (English)

    钟春玲; 叶增; 张云龙

    2012-01-01

    In the prestressed concrete bridge reinforcement, the application of the external prestressed gradually widely. This paper mainly based on differential equation deduced the external prestressed continuous beam in the vertical concentrated load dint method, the analytical solution of the equation. Using this theory calculation in the vertical deflection under concentrated load along the beam long distribution curve and Ansys numerical analysis re- suits are compared, and both have good consistency, it is shown that the result is reasonable and credible. Contrast the result indicates that the analytical solution and can get in the normal service condition the deflection of the con- crete beams, for the future analysis of the external prestressed carbon fiber reinforced the continuous girder provides the foundation.%在预应力混凝土桥梁加固中,体外预应力的应用逐渐广泛.本文主要基于微分方程,推导了体外预应力连续梁在竖向集中荷载作用下力法方程的解析解.利用该理论,计算了在竖向集中荷载作用下的挠度沿梁长的分布曲线,并与Ansys数值分析结果进行了对比,二者具有较好的一致性,说明该计算结果是合理的,可信的.对比结果表明,采用该解析解并能够得到在正常使用状态下混凝土梁的变形情况,为今后分析碳纤维加固体外预应力连续梁提供了基础.

  11. Executive Compensation: A Brief Review

    OpenAIRE

    Bognanno, Michael L.

    2010-01-01

    Chief executive officer (CEO) compensation is defined as the sum of base pay, bonuses, stock grants, stock options, other forms of compensation and benefits. Inflation?adjusted, median total CEO compensation in the United States almost tripled between 1992 and 2000, with grants of stock options evolving to be the largest component of compensation. This article presents the arguments for and against this level and composition of CEO compensation.

  12. A Novel Frequency Compensation Technique for Three-Stage Amplifier

    Institute of Scientific and Technical Information of China (English)

    LI Qiang; YI Jun; LI Zhao-ji; ZHANG Bo; FANG Jian; LUO Ping

    2005-01-01

    A novel frequency compensation technique for three-stage amplifier with dual complex pole-zero (DCP) cancellation is proposed. It uses one pair of complex zeros to cancel one pair of complex poles, resulting in feature that frequency response of the three-stage amplifier exhibits that of a single-pole system. Thus the gain-bandwidth (GBW) is expected to be increased several times compared to the conventional nested miller compensation (NMC) approach. Moreover, this technique requires only one very small compensation capacitor even when driving a big load capacitor. A GBW 4.63 MHz, DC gain 100 dB, PM 90o and power dissipation 0.87 mW can be achieved for a load capacitor 100 pF with a single Miller compensation capacitor 2 pF at a ±1V supply in a standard 0.6-μm CMOS technology.

  13. Experimental demonstration of benchtop x-ray fluorescence computed tomography (XFCT) of gold nanoparticle-loaded objects using lead- and tin-filtered polychromatic cone-beams.

    Science.gov (United States)

    Jones, Bernard L; Manohar, Nivedh; Reynoso, Francisco; Karellas, Andrew; Cho, Sang Hyun

    2012-12-07

    This report presents the first experimental demonstration, to our knowledge, of benchtop polychromatic cone-beam x-ray fluorescence computed tomography (XFCT) for a simultaneous determination of the spatial distribution and amount of gold nanoparticles (GNPs) within small-animal-sized objects. The current benchtop experimental setup successfully produced XFCT images accurately showing the regions containing small amount of GNPs (on the order of 0.1 mg) within a 3 cm diameter plastic phantom. In particular, the performance of the current XFCT setup was improved remarkably (e.g., at least a factor of 3 reduction in XFCT scan time) using a tin-filtered polychromatic beam in comparison with a lead-filtered beam. The results of this study strongly suggest that the current benchtop XFCT configuration can be made practical with a few modifications such as the deployment of array detectors, while meeting realistic constraints on x-ray dose, scan time and image resolution for routine pre-clinical in vivo imaging with GNPs.

  14. STABILITY OF FGM BEAM UNDER ACTION OF NON-CONSERVATIVE FORCE AND THERMAL LOADS%非保守力和热载荷作用下FGM梁的稳定性

    Institute of Scientific and Technical Information of China (English)

    赵凤群; 王忠民

    2012-01-01

    The stability of a FGM beam under the action of thermal loads and a uniformly distributed tangential follower force is analyzed.The material properties(Young’s modulus and mass density) of the beam are assumed to be varied continuously through the height direction according to a simple power-law distribution in terms of volume fraction of material constituents,and to be temperature-dependent.The temperature distribution of FGMs is assumed to be varied through the height direction following a one-dimensional steady-state heat conduction equation.The variation of Young’s modulus along the thickness of the beam for different values of graded index and temperature are calculated.The governing differential equations built on Euler-Bernoulli beam theory for the FGM beam are solved by using a WDQ method.The effect of the graded index,temperature,and follower force on vibration behaviors and stability of a simple supported non-conservative FGM beam are discussed.%研究了在热载荷和切向均布随从力作用下FGM梁的稳定性问题。假设材料常数(即弹性模量和密度)随温度及沿截面高度连续变化,且材料常数按各材料的体积分数以幂率变化,温度分布满足一维热传导方程,计算了不同梯度指标和不同温度下FGM梁的弹性模量随截面高度变化情况。基于Euler-Bernoulli梁理论,建立梁的控制微分方程,用小波微分求积法(WDQ法)求解,分析了梯度指标、温度、随从力等参数对简支FGM梁振动特性与稳定性的影响。

  15. 复合材料夹芯梁屈曲破坏模式及极限承载%Buckling failure mode and ultimate load of composite sandwich beam

    Institute of Scientific and Technical Information of China (English)

    陈悦; 朱锡; 李华东; 朱子旭

    2016-01-01

    In order to investigate the buckling,postbuckling characteristics and load capacity of composite sand-wich beam under the effect of axial compression,test investigation and finite element simulation were carried out. Firstly,a series of buckling characteristic tests of composite sandwich beams were conducted.The effects of ply ra-tio angle,length of beam,face layer thickness and core layer thickness on buckling,postbuckling failure modes and ultimate load were discussed.Then,based on the nonlinear buckling theory,3D cohesive interface elements were used to simulate the debond between skin and core,and initial predeformation as well as material damage criteria were also introduced to simulate and investigate the buckling characteristics and ultimate load of composite sandwich beam under axial compression.The results show that interface debond is the important mode of buckling failure. Comparing the ultimate load calculated by simulation with the test results,the errors are controlled within 10%. The conclusions obtained prove that the method can predict the postbuckling path,failure mode and ultimate load ac-curately.%为研究复合材料夹芯梁在轴压作用下的屈曲、后屈曲特性及承载能力,进行了试验研究与有限元仿真。首先,开展了系列复合材料夹芯梁屈曲特性试验,研究了铺层比例、梁长度、表层厚度及芯层厚度等因素对其屈曲、后屈曲破坏模式及极限承载的影响;然后,基于非线性屈曲理论,采用三维内聚力界面单元模拟面芯脱粘,并引入初始预变形及材料损伤准则对复合材料夹芯梁在轴压下的屈曲特性及极限承载进行仿真研究。结果显示:界面脱粘是屈曲破坏的重要模式;仿真计算的极限承载与试验结果相比,误差控制在10%以内。所得结论表明该方法可有效预报复合材料夹芯梁的后屈曲路径、破坏模式及极限承载。

  16. Oblique Alfvén instabilities driven by compensated currents

    Energy Technology Data Exchange (ETDEWEB)

    Malovichko, P. [Main Astronomical Observatory, NASU, Kyiv (Ukraine); Voitenko, Y.; De Keyser, J., E-mail: voitenko@oma.be [Solar-Terrestrial Centre of Excellence, Space Physics Division, Belgian Institute for Space Aeronomy, Ringlaan-3-Avenue Circulaire, B-1180 Brussels (Belgium)

    2014-01-10

    Compensated-current systems created by energetic ion beams are widespread in space and astrophysical plasmas. The well-known examples are foreshock regions in the solar wind and around supernova remnants. We found a new oblique Alfvénic instability driven by compensated currents flowing along the background magnetic field. Because of the vastly different electron and ion gyroradii, oblique Alfvénic perturbations react differently on the currents carried by the hot ion beams and the return electron currents. Ultimately, this difference leads to a non-resonant aperiodic instability at perpendicular wavelengths close to the beam ion gyroradius. The instability growth rate increases with increasing beam current and temperature. In the solar wind upstream of Earth's bow shock, the instability growth time can drop below 10 proton cyclotron periods. Our results suggest that this instability can contribute to the turbulence and ion acceleration in space and astrophysical foreshocks.

  17. DAFNE Lifetime Optimization with Octupoles and Compensating Wires

    CERN Document Server

    Milardi, C; Preger, M A; Raimondi, P; Zobov, M; Shatilov, D

    2008-01-01

    Long-range beam-beam interactions (parasitic crossings) were one of the main luminosity performance limitations for the lepton F-factory DAFNE in its original configuration. In particular, the parasitic crossings led to a substantial lifetime reduction of both beams in collision. This puts a limit on the maximum storable current and, as a consequence, on the achievable peak and integrated luminosity. In order to mitigate the problem, numerical and experimental studies of the parasitic crossings compensation by current-carrying wires have been done. During the operation for the KLOE experiment two such wires have been installed at both ends of the interaction region. They produced a relevant improvement in the lifetime of the weak beam (positrons) at the maximum current of the strong one (electrons) without luminosity loss, in agreement with the numerical predictions. The same compensating mechanism has been adopted during the run for the FINUDA experiment as well, with less evident benefits than in the previo...

  18. Power factor compensation

    Energy Technology Data Exchange (ETDEWEB)

    Barra R, Felipe [Schneider Electric Chile (Chile)

    2010-07-01

    Every company is looking for ways to increase productivity as a way to gain a competitive advantage. Energy is a significant element in making any product and so it is important to assess production processes from an energy perspective. This paper discusses the impact of power factor compensation on energy efficiency. The life cycle solution for energy efficiency involves optimization of active energy using automation and regulation. A brief explanation is given of how each component of a company plays a part in this cycle. Examples include simulations and analysis, modeling, performance monitoring facilities, and environmental sustainability. Reactive energy suppliers and the installation of capacitors are also explained. Types of compensation include fixed and automation compensations. Economic advantages include a reduction in the electricity bill and active energy consumption. Technical advantages include reduction in voltage drop and an increase in available power. The power correction factor also improves reliability and contributes to conservation of the environment.

  19. Compensation neurosis rides again.

    Science.gov (United States)

    Levy, A

    1992-01-01

    Compensation neurosis (CN), also known as accident neurosis, has generally not been considered to be a 'real' disorder. In 1961 it was seemingly laid to rest by Henry Miller, a distinguished neurologist, in a sharp article which appeared in the British Medical Journal. Miller's view of patients who presented psychological symptoms following accidents or traumas was suspicious. Compensated or not, his view seemed to be that they should have their legal process finished as quickly as possible and then they will miraculously convalescence. Miller's work, it appeared, was the coup de grâce for this ill-defined diagnosis. Today, however, compensation neurosis seems to ride again. After a prolonged silence in the psychiatric literature, new papers are emerging, strongly suggesting that this vanishing diagnosis be reconsidered. This new trend will be presented.

  20. T1 VSAT Fade Compensation Statistical Results

    Science.gov (United States)

    Johnson, Sandra K.; Acosta, Roberto; Ugweje, Oke

    2000-01-01

    New satellite communication systems are steadily seeking to use higher frequency bands to accommodate the requirements for additional capacity. At these higher frequencies, propagation impairments that did not significantly affect the signal at lower frequencies begin to have considerable impact. In Ka-band. the next logical commercial frequency band to be used for satellite communication, attenuation of the signal due to rain is a primary concern. An experimental satellite built by NASA, the Advanced Communication Technology Satellite (ACTS). launched in September 1993, is the first U.S. communication satellite operating in the Ka-band. In addition to higher carrier frequencies, a number of other new technologies, including on-board baseband processing. multiple beam antennas, and rain fade detection and compensation techniques, were designed into the ACTS. Verification experiments have been conducted since the launch to characterize the new technologies. The focus of this paper is to characterize the method used by the ACTS TI Very Small Aperture Terminal (TI VSAT) ground stations in detecting the presence of fade in the communication signal and to adaptively compensate for it by the addition of burst rate reduction and forward error correction. Measured data obtained from the ACTS program was used to validate the compensation technique. A software process was developed and demonstrated to statistically characterize the increased availability achieved by the compensation techniques in terms of the bit error rate time enhancement factor. Several improvements to the ACTS technique are discussed and possible implementations for future Ka band system are offered.

  1. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    Science.gov (United States)

    Bonomo, F.; Ruf, B.; Barbisan, M.; Cristofaro, S.; Schiesko, L.; Fantz, U.; Franzen, P.; Pasqualotto, R.; Riedl, R.; Serianni, G.; Wünderlich, D.

    2015-04-01

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the Hα light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of Hα spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  2. Depth profiling of taxol-loaded poly(styrene- b-isobutylene- b-styrene) using Ga + and C 60+ ion beams

    Science.gov (United States)

    Braun, R. M.; Cheng, J.; Parsonage, E. E.; Moeller, J.; Winograd, N.

    2006-07-01

    The surface of a triblock copolymer, containing a solid-phase drug, was investigated using 15 keV Ga + and 20 keV C 60+ ion beams. Overall, the results illustrate the successful use of a cluster ion beam for greatly enhancing the molecular ion and high-mass fragment ion intensities from the surface and bulk of the polymer system. The use of C 60+ also established the ability to see through common overlayers like poly(dimethyl siloxane) which was not possible using atomic ion sources. Moreover, the use of C 60+ allowed depth profiles to be obtained using primary ion dose densities in excess of 6 × 10 14 C 60+/cm 2. Resulting sputter craters possess relatively flat bottoms without the need for sample rotation and reached depths of ca. 2 μm. AFM results illustrate the more gentile removal of surface species using cluster ions. Specifically, phase contrast and topographic images suggest the relatively high ion doses do not significantly alter the phase distribution or surface topography of the polymer. However, a slight increase in rms roughness was noticed.

  3. Depth profiling of taxol-loaded poly(styrene-b-isobutylene-b-styrene) using Ga{sup +} and C{sub 60} {sup +} ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Braun, R.M. [Surface Science Laboratory, Bausch and Lomb Inc., Rochester, NY 14609 (United States)]. E-mail: rbraun@bausch.com; Cheng, J. [Department of Chemistry, Penn State University, University Park, PA 16802 (United States); Parsonage, E.E. [Boston Scientific Inc., Maple Grove, MN 55311-1566 (United States); Moeller, J. [Boston Scientific Inc., Maple Grove, MN 55311-1566 (United States); Winograd, N. [Department of Chemistry, Penn State University, University Park, PA 16802 (United States)

    2006-07-30

    The surface of a triblock copolymer, containing a solid-phase drug, was investigated using 15 keV Ga{sup +} and 20 keV C{sub 60} {sup +} ion beams. Overall, the results illustrate the successful use of a cluster ion beam for greatly enhancing the molecular ion and high-mass fragment ion intensities from the surface and bulk of the polymer system. The use of C{sub 60} {sup +} also established the ability to see through common overlayers like poly(dimethyl siloxane) which was not possible using atomic ion sources. Moreover, the use of C{sub 60} {sup +} allowed depth profiles to be obtained using primary ion dose densities in excess of 6 x 10{sup 14} C{sub 60} {sup +}/cm{sup 2}. Resulting sputter craters possess relatively flat bottoms without the need for sample rotation and reached depths of ca. 2 {mu}m. AFM results illustrate the more gentile removal of surface species using cluster ions. Specifically, phase contrast and topographic images suggest the relatively high ion doses do not significantly alter the phase distribution or surface topography of the polymer. However, a slight increase in rms roughness was noticed.

  4. 静载荷作用下钢筋混凝土变截面梁桥有限元仿真%Finite Element Simulation of Reinforced Concrete Tapered Beam Bridge under Static Loading

    Institute of Scientific and Technical Information of China (English)

    魏湛力; 褚少辉; 张涛; 张艳玲

    2016-01-01

    With the rapid development of China's transport business and increasing load of highway and bridge, coupled with the geographic conditions of many mountains and rivers in China, bridge design and construction is attracting more and more attention. In new bridge design, bridge construction monitoring and finished bridge test, the calculation of stress, strain and deflection is extremely important. This paper uses finite element analysis software ANSYS for static analysis of continuous variable cross-section beam bridge model, mainly to comprehensively evaluate the stress level of tapered beam through analysis and comparison of deformation figure and stress diagram under different loading, in order to provide reference for further study of other characteristic of the continuous variable cross-section bridge and structural optimization.%随着我国交通事业的高速发展,公路桥梁负荷的日益加重,再加上我国多河流山川的地理条件,桥梁设计和施工越来越受到重视。在新桥设计、桥梁施工监控和成桥试验检测中,应力、应变,挠度计算都极其重要。利用有限元分析软件ANSYS对连续变截面梁桥模型进行静力分析,主要是通过分析对比不同载荷作用下的变形图、应力图,全面评价变截面梁的应力水平,为进一步研究连续变截面梁桥的其它特性和结构优化提供参考。

  5. 集中载荷作用下饱和多孔Timoshenko简支梁的动力响应%DYNAMICAL BEHAVIOR OF SIMPLY-SUPPORTED SATURATED POROELASTIC TIMOSHENKO BEAM UNDER A CONCENTRATED LOAD

    Institute of Scientific and Technical Information of China (English)

    欧阳煜; 张雅男

    2012-01-01

    Based on the mathematical model for dynamics of a saturated poroelastic Timoshenko beam, the dynamical behavior of a simply-supported saturated poroelastic Timoshenko beam, with two permeable ends and subjected to a sudden step load at its midpoint, is investigated. The analytical solution is obtained, and the variations of the dimensionless deflections, bending moments of the solid skeleton of the poroelastic beam, and equivalent couples of the pore fluid pressure against the dimensionless time are given. The effects of the shearing and rotation inertia of the cross section on the dynamical behavior are examined, and the dynamical behaviors of the saturated poroelastic Timoshenko, Shear, Rayleigh and Euler-Bernoulli beams are compared. It is shown that the shearifig effect increases the amplitudes and periods of the dynamical responses of the saturated poroelastic Timoshenko beam, while the rotation inertia effect of the cross section only increases the periods. The interaction between the solid skeleton and pore fluid plays a role as viscidity. With the interaction coefficient increasing, the deflections and bending moments of the saturated poroelastic beam decrease, and the amplitudes of the equivalent couple of the pore fluid pressure increase, furthermore, the attenuation of the vibration amplitudes is more rapidly with the increasing of the interaction coefficient. Meanwhile, with the slenderness ratio increasing, the amplitude and period of the saturated poroelastic Timoshenko beam decrease gradually, and they converge to those of the saturated poroelastic Euler-Bernoulli beam.%基于饱和多孔弹性Timoshenko梁的动力数学模型,研究了梁中点承受突加载荷作用两端可渗透饱和多孔弹性Timoshenko简支梁的动力响应,得到了问题的解析解,给出了梁中点无量纲挠度、固相骨架弯矩和孔隙流体压力等效力偶等随无量纲时间的响应。考察了剪切和横截面转动惯性效应等对动力响应

  6. Analysis and Design of Backing Beam for Multipole Wiggler (MPW14) at PLS

    CERN Document Server

    Lee, Hong-Gi; Jung, Young-Gyu; Park, Ki-Hyeon; Sik Han, Hong; Suck Suh, Hyung; Wha Chung, Chin; Woo Lee, Wol

    2005-01-01

    Pohang Accelerator Laboratory (PAL) had developed and installed a Multipole Wiggler (MPW14) to utilize high energy synchrotron radiation at Pohang Light Source (PLS). The MPW14 is a hybrid type device with period of 14 cm, minimum gap of 14 mm, maximum flux density of 2.02 Tesla and total magnetic structure length of 2056 mm. The support locations and structure of an insertion device are optimized to achieve a minimum deflection due to the magnetic loads. A Finite Element Analysis (FEA) is performed to find out the amount of maximum deflection and optimal support positions on the backing beam, the support and drive structures of the MPW14 under expected magnetic load of 14 tons. To reduce the deflection effect further, two springs are designed and installed to compensate the gap dependent magnetic loads. The optimized deflection is estimated to be about 20.6 ? while the deflection before optimization is 238 ?.

  7. 贝克曼梁法测试水泥砼路面弯沉及路面持荷能力评价%Backman Beam Method Test of Cement Concrete Pavement Deflection and Pavement Loading Capacity Evaluation

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Backman beam method for detection of the cement concrete pavement is widely used at home and abroad, and it is the main method of cement concrete pavement strength of our survey, there are a lot of the joint of cement concrete pavement, in the long-term running effect and infiltration of rainwater ef-fect, very easy to cause the void beneath slab. According to the Backman beam method detection deflection data, this paper pr-oposes treatment scheme on the plate considering the road blo-ck bearing capacity, load transfer capability, and verifies.%  贝克曼梁法检测水泥混凝土路面板底脱空是国内外广泛使用的方法,也是我国水泥混凝土路面路面强度调查的主要方法,水泥混凝土路面有很多接缝,在长期行车作用及雨水渗入作用下,很容易造成板底脱空。本文根据贝克曼梁法检测的弯沉数据,在综合考虑路面板块承载能力、传荷能力的情况对板块提出了处理方案,并进行了实例验证。

  8. 冲击荷载作用下高强钢筋混凝土梁性能试验%Experimental Study on the Behavior of High Strength Reinforced Concrete Beams Under Impact Load

    Institute of Scientific and Technical Information of China (English)

    窦国钦; 杜修力; 李亮

    2014-01-01

    To explore the shear-resistant behavior of RC beams under impact load,six simply-supported high strength RC beam with various shear reinforcement ratios,were tested under free-falling drop-weights,impacting the speci-mens at mid-span,and the effects of impact mass and impact energy on the shear resistant behavior of RC beams were investigated. The crack initiation,propagation and the failure patterns of the specimens were recorded using a high-speed video camera. The characteristics of time history of impact force,support pressure and mid-span dis-placement were described in details. The results obtained are as follows:Experimental studies reveal that shear mechanisms play an important role in the overall impact behavior of RC structures. Severe diagonal shear cracks occur even with statically flexural-critical RC beams tested under impact loads applied at the mid-span. Increase of concrete strength has less effect on the degree of overall failure,but it can reduce the specimen local failure near the impact loading point;This article summarizes the result of independent impact load experiment on the RC beam. It draws out the index that significantly influences between the maximum mid-span displacement and the static ultimate bending strength. It contributes to the impact resistance design method for simply-supported RC beam performance verification;During the initial stage before the external force reached the supports,the impact forces acting on the RC beam were mainly resisted by the inertia force of the specimens. The stiffness of a structure and the span length of a beam are important factors in resisting impact forces.%为深入探讨冲击荷载作用下高强钢筋混凝土(RC)配筋梁的抗冲击性能,利用落锤试验机对6根简支RC梁进行了试验研究,分析了不同冲击锤质量和冲击能量下高强钢筋混凝土梁的抗冲击行为。采用高速摄像机记录了各试件在冲击过程中裂缝发生的过程,记录并分析了

  9. Effect of Initial Load on Static Characteristics of Beams Fixed at One End and Simply Supported at the Other End%初始载荷对一端固支一端简支梁静力特性的影响

    Institute of Scientific and Technical Information of China (English)

    杨治国; 张家玮

    2011-01-01

    研究了初始载荷对一端固支一端简支梁静力特性的影响,得到了其静力计算的闭合解.引入了初始载荷影响系数以反映初始载荷的非线性效应,讨论了初始载荷的大小、梁的截面惯性矩和跨度对初始载荷影响系数的影响.结果表明:当存在初始载荷时,后续载荷所引起的静力反应会减小,其减小程度与初始载荷的大小和梁的刚度参数有关.建议在设计轻型及柔性结构时,对初始载荷的这种非线性影响予以适当考虑.%The effect of initial load on the static characteristics of beams fixed at one end and simply supported at the other end is studied. Based on a nonlinear differential equation of the static responses, the closed -form solutions of static responses for such beams are given, with the effect of initial load considered. An initial load influence factor is introduced to indicate the nonlinear effect of initial load and how it is affected by the magnitude of initial load,sectional moment of inertia and span of the beam is discussed. The results suggest that with the initial load in existence,the static responses induced by later-applied loads would be reduced, the extent of this reduction relates to the magnitude of initial load and stiffness of the beam, and such effect should be appropriately considered in the design of lightweight and flexible structures.

  10. RELIABILITY OF LENTICULAR EXPANSION COMPENSATORS

    Directory of Open Access Journals (Sweden)

    Gabriel BURLACU,

    2011-11-01

    Full Text Available Axial lenticular compensators are made to take over the longitudinal heat expansion, shock , vibration and noise, made elastic connections for piping systems. In order to have a long life for installations it is necessary that all elements, including lenticular compensators, have a good reliability. This desire can be did by technology of manufactoring and assembly of compensators, the material for lenses and by maintenance.of compensator

  11. Thermal lensing compensation for AIGO high optical power test facility

    Science.gov (United States)

    Degallaix, Jérôme; Zhao, Chunnong; Ju, Li; Blair, David

    2004-03-01

    We present finite element modelling of thermal lensing occurring in an interferometer test mass. Our simulations include the thermo-optic effect and mechanical expansion of the optics. For the High Optical Power Test Facility (HOPTF) operated by the Australian International Gravitational Observatory (AIGO), the optical path length measured across the laser beam radius is 45 nm for 1.2 W absorbed power for the input sapphire test mass. The AIGO thermal lens is much stronger than the one in Advanced LIGO and will degrade the interferometer performance. Direct thermal compensation and the use of an external compensation plate were investigated to minimize thermal lensing consequences in the interferometer. For the AIGO situation, a fused silica external plate is the most practical solution to correct thermally induced wavefront distortions. The compensation plate requires lower thermal power than direct compensation and does not increase the test mass temperature.

  12. Thermal lensing compensation for AIGO high optical power test facility

    Energy Technology Data Exchange (ETDEWEB)

    Degallaix, Jerome [School of Physics, University of Western Australia, Stirling Highway, Crawley, WA 6009 (Australia); Zhao Chunnong [Computer and Information Science, Edith Cowan University, Mount Lawley, WA 6050 (Australia); Ju Li [School of Physics, University of Western Australia, Stirling Highway, Crawley, WA 6009 (Australia); Blair, David [School of Physics, University of Western Australia, Stirling Highway, Crawley, WA 6009 (Australia)

    2004-03-07

    We present finite element modelling of thermal lensing occurring in an interferometer test mass. Our simulations include the thermo-optic effect and mechanical expansion of the optics. For the High Optical Power Test Facility (HOPTF) operated by the Australian International Gravitational Observatory (AIGO), the optical path length measured across the laser beam radius is 45 nm for 1.2 W absorbed power for the input sapphire test mass. The AIGO thermal lens is much stronger than the one in Advanced LIGO and will degrade the interferometer performance. Direct thermal compensation and the use of an external compensation plate were investigated to minimize thermal lensing consequences in the interferometer. For the AIGO situation, a fused silica external plate is the most practical solution to correct thermally induced wavefront distortions. The compensation plate requires lower thermal power than direct compensation and does not increase the test mass temperature.

  13. Compensability index for compensation radiotherapy after treatment interruptions

    Directory of Open Access Journals (Sweden)

    Putora Paul

    2012-12-01

    Full Text Available Abstract Background The goal of our work was to develop a simple method to evaluate a compensation treatment after unplanned treatment interruptions with respect to their tumour- and normal tissue effect. Methods We developed a software tool in java programming language based on existing recommendations to compensate for treatment interruptions. In order to express and visualize the deviations from the originally planned tumour and normal tissue effects we defined the compensability index. Results The compensability index represents an evaluation of the suitability of compensatory radiotherapy in a single number based on the number of days used for compensation and the preference of preserving the originally planned tumour effect or not exceeding the originally planned normal tissue effect. An automated tool provides a method for quick evaluation of compensation treatments. Conclusions The compensability index calculation may serve as a decision support system based on existing and established recommendations.

  14. Experiences with active damping and impedance-matching compensators

    Science.gov (United States)

    Betros, Robert S.; Alvarez, Oscar S.; Bronowicki, Allen J.

    1993-09-01

    TRW has been implementing active damping compensators on smart structures for the past five years. Since that time there have been numerous publications on the use of impedance matching techniques for structural damping augmentation. The idea of impedance matching compensators came about by considering the flow of power in a structure undergoing vibration. The goal of these compensators is to electronically dissipate as much of this flowing power as possible. This paper shows the performance of impedance matching compensators used in smart structures to be comparable to that of active damping compensators. Theoretical comparisons between active damping and impedance matching methods are made using PZT actuators and sensors. The effects of these collocated and non-collocated PZT sensors and actuators on the types of signals they sense and actuate are investigated. A method for automatically synthesizing impedance matching compensators is presented. Problems with implementing broad band active damping and impedance matching compensators on standard Digital Signal Processing (DSP) chips are discussed. Simulations and measurements that compare the performance of active damping and impedance matching techniques for a lightly damped cantilevered beam are shown.

  15. Compensation for Occupational Cancer

    OpenAIRE

    Kim, Inah; Kim, Eun-A; Kim, Jae Young

    2014-01-01

    The legal scope and criteria for occupational cancer in Korea was out of date. The aim of this study was to review the current criteria for occupational cancer and amend the existent criteria on the basis of recent scientific evidence. The scientific evidence and the legal list of occupational cancer were analyzed to identify the causes of occupational cancer on a global scale. The relationship between compensated occupational cancer cases and carcinogen exposure in Korea was examined. The fa...

  16. Adaptive compensation of a direct liquid-cooled solid-state MOPA system

    Science.gov (United States)

    Dong, Lizhi; Chen, Shanqiu; Chen, Xiaojun; Liu, Wenjin; Hu, Ke; Lai, Boheng; Yang, Ping; Wang, Shuai; He, Xing; Xu, Bing; Liu, Le; Liu, Yang; Wang, Zhe; Wang, Gang

    2016-09-01

    Direct liquid-cooling is a promising way of power scaling and heat management for solid-state lasers. A side-pumped direct liquid-cooled solid-state pulsed zigzag MOPA system is established based on this advanced concept. However, its beam quality is degraded by the thermal distortions in the non-zigzag direction and the flowing coolant. We develop an adaptive optics system to improve its beam quality, which primarily includes a low-order aberration compensator and a 59-actuator deformable mirror. The beam is first corrected by the low-order aberration compensator to remove large defocus and astigmatism, and its size is reshaped simultaneously to fulfill the demands of applications. Then the beam is further corrected by the deformable mirror. With collaborative operation of the low-order aberration compensator and the deformable mirror, we have achieved average beam quality of β=2.8.

  17. Fatigue behavior of RC T-beams

    Directory of Open Access Journals (Sweden)

    Omar A. Farghal

    2014-09-01

    Full Text Available The objective of this research is to study the fatigue performance of reinforced concrete (RC T-beams strengthened in shear with Carbon Fiber Reinforced Polymer (CFRP composite. Experiments were conducted on RC beams with and without CFRP sheets bonded on their web surfaces and subjected to static and cycling loading. The obtained results showed that the strengthened beams could survive one million cycles of cyclic loading (=50% of maximum static load with no apparent signs of damage (premature failure demonstrating the effectiveness of CFRP strengthening system on extending the fatigue life of structures. Also, for beams having the same geometry, the applied strengthening technique can significantly enhance the cycling load particularly, in case of beams provided with U-jacket sheets. Moreover, although the failure mode for the different beams was a brittle one, the strengthened beams provided with U-jacket sheets approved an acceptable enhancement in the structural ductility.

  18. Beam stability at CTF3

    CERN Document Server

    Persson, T

    2012-01-01

    The two-beam acceleration tested at CTF3 imposes very tight tolerances on the drive beam stability. A description of the specialized monitoring tool developed to identify the drifts and jitter in the machine is presented. It compares all the relevant signals in an on-line manner to help the operator to identify drifts and to log data for off-line analysis. The main sources for the drifts of the drive beam have been identified and their causes are described. A feedback applied to the RF was implemented to reduce the effects. It works by changing the waveform for the pulse compression to compensate for the drifts.

  19. Standard Test Method for Measuring the Curved Beam Strength of a Fiber-Reinforced Polymer-Matrix Composite - (View Full Text) D6416/D6416M-01(2007) Standard Test Method for Two-Dimensional Flexural Properties of Simply Supported Sandwich Composite Plates Subjected to a Distributed Load

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    Standard Test Method for Measuring the Curved Beam Strength of a Fiber-Reinforced Polymer-Matrix Composite - (View Full Text) D6416/D6416M-01(2007) Standard Test Method for Two-Dimensional Flexural Properties of Simply Supported Sandwich Composite Plates Subjected to a Distributed Load

  20. Analysis and Compensation of Commutated Current Freewheeling for Sensorless Brushless DC Motor Under Heavy-load Condition%重载条件下无刷直流电机无位置传感器驱动换相续流影响的分析及其补偿

    Institute of Scientific and Technical Information of China (English)

    杨明; 刘杰; 徐殿国

    2013-01-01

    At the communication moment of brushless DC motor (BLDCM), the terminal voltage is distorted by diode freewheeling current from which phase current will be turn off. Taking the back-EMF zero-cross detection method in sensorless position control, this terminal voltage distortion can make position detection signal phase ahead, deviating from the best commutation time, especially, in heavy-load condition it can cause commutation failure. Therefore back-EMF zero-cross detection method has been restricted in light-power application. The mechanism of freewheeling current causes advance signal has been analyzed in this paper, and based mathematical model, a position detection signal phase ahead compensation method is presented too. Simulation and experimental results show that the compensated signal is close to the best commutation time, BLDC motor can still be normal operation by sensorless control with heavy-load.%无刷直流电机(brushless DC motor,BLDCM)换相时刻关断相电流的续流造成电机端电压的畸变。当采用无位置传感器反电动势过零检测法时,端电压波形畸变会使位置检测信号相位超前,偏离最佳换相时刻,重载条件下甚至会造成换相失败,制约了反电动势检测法的电机功率应用范围。因此,该文针对电流续流影响端电压的机理加以分析,建立了电流续流产生相位超前的数学模型,并给出了位置检测信号相位超前的补偿算法。仿真和实验结果表明,经过补偿后的位置检测接近最佳换相时刻,重载条件下仍可正常运行。

  1. Analysis of emittance compensation and simulation results to photo-cathode RF gun

    CERN Document Server

    LiuShengGuang

    2002-01-01

    The emittance compensation technology will be used on the photo-cathode RF gun for Shanghai SDUV-FEL. The space charge force and its effect on electron beam transverse emittance in RF gun is studied, the principle of emittance compensation in phase-space is discussed. The authors have designed a compensation solenoid and calculated its magnetic field distribution. Its performance has been studied by the code PARMELA. A simulation result indicates that the normalized transverse RMS emittance for electron beam of 1.5 nC is 1.612 pi mm centre dot mrad, electron energy E = 5.71 MeV

  2. 初始荷载对RC梁碳纤维布抗弯加固效果影响的有限元分析%Finite-element Analysis of Effect of Initial Load on Bending Capacity of Reinforced Concrete Beam Strengthened with CFRP

    Institute of Scientific and Technical Information of China (English)

    武志杰; 陈悦

    2013-01-01

    利用ANSYS建立14根碳纤维布加固钢筋混凝土简支梁模型,分析在两种配筋率情况下,不同初始荷载对钢筋混凝土梁碳纤维布抗弯加固效果的影响。结果表明:碳纤维布加固可显著提高梁的屈服荷载和极限荷载,梁的屈服荷载和极限荷载的提高幅度随着初始荷载的增加而减小;配筋率越小,受拉钢筋利用越充分,梁的极限荷载提高幅度越明显。%Fourteen reinforced concrete simply supported beam models with CFRP sheets were built by using ANSYS, and the influence of different initial loads on the reinforcement and flexural strength effects of CFRP sheets in two steel rein-forcement ratios was analyzed. The results indicated that reinforced carbon fiber sheet could significantly increase the yield-ing load and ultimate load of the beam. The enhancement of yielding load and ultimate load decreased with the increase of initial load. The more adequate the steel reinforcement utilization rate was, the more significantly the ultimate load with small reinforcement ratio would be improved.

  3. Self Organization in Compensated Semiconductors

    Science.gov (United States)

    Berezin, Alexander A.

    2004-03-01

    In partially compensated semiconductor (PCS) Fermi level is pinned to donor sub-band. Due to positional randomness and almost isoenergetic hoppings, donor-spanned electronic subsystem in PCS forms fluid-like highly mobile collective state. This makes PCS playground for pattern formation, self-organization, complexity emergence, electronic neural networks, and perhaps even for origins of life, bioevolution and consciousness. Through effects of impact and/or Auger ionization of donor sites, whole PCS may collapse (spinodal decomposition) into microblocks potentially capable of replication and protobiological activity (DNA analogue). Electronic screening effects may act in RNA fashion by introducing additional length scale(s) to system. Spontaneous quantum computing on charged/neutral sites becomes potential generator of informationally loaded microstructures akin to "Carl Sagan Effect" (hidden messages in Pi in his "Contact") or informational self-organization of "Library of Babel" of J.L. Borges. Even general relativity effects at Planck scale (R.Penrose) may affect the dynamics through (e.g.) isotopic variations of atomic mass and local density (A.A.Berezin, 1992). Thus, PCS can serve as toy model (experimental and computational) at interface of physics and life sciences.

  4. 38 CFR 3.4 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Compensation. 3.4 Section..., Compensation, and Dependency and Indemnity Compensation General § 3.4 Compensation. (a) Compensation. This term...) Disability compensation. (1) Basic entitlement for a veteran exists if the veteran is disabled as the...

  5. Compensation for Power Quality Improvement in Electric Arc Furnace with Considering Economic Index

    Directory of Open Access Journals (Sweden)

    Ghazanfar Shahgholian

    2012-03-01

    Full Text Available In recent years, on the one hand with increasing application of nonlinear loads in power systems and no sinusoidal currents that extracted from system, and on the other hand increasing loads sensitive to power quality and destructive effects of nonlinear loads on power quality of power systems, compensation these loads has been converted to one of the main issues in power systems. The use of flexible AC transmission system (FACTS devices is one of the most progressive methods which are used for improving power quality. In this paper, series and parallel compensators of static synchronous compensator (STATCOM and dynamic voltage restorer (DVR are introduced and the comparison of these two in compensating of power quality phenomena from electric arc furnace is provided. STATCOM is a shunt active filter and DVR is a series active filter. Method which has been selected for control of every one of these devices is an optimal control way that it minimizes power losses.

  6. A controllable resistor and its applications in pole-zero tracking frequency compensation methods for LDOs

    Institute of Scientific and Technical Information of China (English)

    Wang Yi; He Lenian; Ning Zhihua; Shao Yali

    2009-01-01

    unit-gain compensation ceil and pseudo-ESR (equivalent serial resistor of load capacitor) power stage have been realized by this controllable resistor.Their advantages and limitations are discussed and verified by simulation results.

  7. Feedback Control of Transmission Line by Static VAR Compensators (TSC & TCR Using Fuzzy Logic

    Directory of Open Access Journals (Sweden)

    Arushi Jaiswal

    2013-07-01

    Full Text Available Voltage profile maintenance of a transmission system can be done by using feedback control methodology and the compensation technique used is Static VAR compensation. This thesis describes a MATLAB based SIMULINK model that can be implemented in real time systems to maintain a constant voltage profile during load changes and fault conditions. In any power system the basic requirement is to keep the voltage of the system constant so that the load functions properly. Whenever there is a fault or any load is disconnected, the active and reactive power requirements of the system changes. As a result, the voltage of the system changes. Therefore to maintain a constant voltage profile shunt compensators are used near the load end, in the model presented in this project. Fuzzy logic is also implemented to set the proper compensation required

  8. Research on deflection pre-compensation of upper roller for large marine bending machine%大型船用卷板机上辊挠曲变形预补偿研究

    Institute of Scientific and Technical Information of China (English)

    陈兰; 张新洲; 孙字; 杨树田; 常欣

    2011-01-01

    针对大型卷板机上辊挠曲变形的补偿难题,利用ANSYS有限元优化方法,对某21 m大型船用卷板机的上辊支承辊的数量、位置及施加载荷的分布进行了合理优化,进而提出了挠度补偿措施.结合有限元分析方法分别得到了上辊和上梁在优化载荷作用下和整体模型在工作载荷作用下的挠曲变形,并对预补偿后的情况进行了分析,补偿后上辊的最大挠度是0.71 mm,几乎能使上辊趋于水平,结果满足卷板机上辊挠曲变形的补偿要求.%In order to solve the problem of deflection compensation of upper roller for large marine bending machine, using FEA optimization method based on ANSYS, the amount, locations and the imposed loads of bearing rollers of 21 m large marine bending machine were optimized reasonably and the deflection compensation measure was proposed. The deflection of the upper roller and beam in optimizing loads and overall role model in the working load were obtained through finite element analysis method. After compensation, the maximum deflection is 0. 71 mm, the upper roller almost tends to be level. The result of pre-compensation by finite element analysis method shows that it is feasible for deflection compensation of upper roller for large marine bending machine.

  9. The Study,Analysis and Calculations of Balance Compensation for the Impedance Matching Balance Transformer When Carrying Single Phase Load%阻抗匹配平衡变压器单相负荷平衡补偿 的研究与分析计算

    Institute of Scientific and Technical Information of China (English)

    熊芝耀; 程敏胜; 张志文; 刘福生

    2001-01-01

    The Balance Transformer Accroding to Impedance Matching which has been widely used in electric railway is a kind of three-phase to two-phase power supply equipment.The single phase load is generally not considered as balance,but its balance transformation can be realized by compensation.When the capacity of power supply network is not so large compared with that of the single phase loads that it can not bear the negative influence,the theory discussed in this paper render the primary three phase system symmetry.This paper analyses and calculates the related condition of single phase transformation of balance in details.The test of practical model proves its feasibility.%阻抗匹配平衡变压器,是一种三相变两相的供电设备,已广泛用于我国电气化铁道。对于单相负荷,通常原方三相电流是不平衡的,但通过补偿,也可实现平衡变换。这一新的发现,对有的单相负荷容量较大,且电网容量不大,经受不了较大负序干扰的地方,能使原方三相系统保持对称运行。本文对单相平衡变换的条件进行了较详细的分析和计算并通过模型机试验,验证了其可行性。

  10. Urban agglomeration and CEO compensation

    OpenAIRE

    Francis, Bill; Hasan, Iftekhar; John, Kose; Waisman , Maya

    2012-01-01

    An underlying assumption in the executive compensation literature is that there is a national labor market for CEOs. The urban economics literature, however, documents higher ability among workers in large metropolitans, which results in a real and stable urban wage premium. In this paper, we investigate the link between the spatial clustering of firms in big, central cities (i.e., urban agglomeration) and the level and structure of CEO compensation. Using CEO compensation data for the period...

  11. Numerical Calculation of Beam Coupling Impedances in the Frequency Domain using FIT

    CERN Document Server

    Niedermayer, U

    2012-01-01

    The transverse impedance of kicker magnets is considered to be one of the main beam instability sources in the projected SIS-100 at FAIR and also in the SPS at CERN. The longitudinal impedance can contribute to the heat load, which is especially a concern in the cold sections of SIS-100 and LHC. In the high frequency range, commercially available time domain codes like CST Particle Studio serve to calculate the impedance but they are inapplicable at medium and low frequencies which become more important for larger size synchrotrons. We present the ongoing work of developing a Finite Integration Technique (FIT) solver in frequency domain which is based on the Parallel and Extensible Toolkit for Scientific computing (PETSc) framework in C++. Proper beam adapted boundary conditions are important to validate the concept. The code is applied to an inductive insert used to compensate the longitudinal space charge impedance in low energy machines. Another application focuses on the impedance contribution of a ferrit...

  12. BATMAN beam properties characterization by the beam emission spectroscopy diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Bonomo, F., E-mail: federica.bonomo@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Istituto Gas Ionizzati - CNR, Corso Stati Uniti 4, 35127 Padova (Italy); Ruf, B.; Schiesko, L.; Fantz, U.; Franzen, P.; Riedl, R.; Wünderlich, D. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany); Barbisan, M.; Pasqualotto, R.; Serianni, G. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Cristofaro, S. [Universitá degli Studi di Padova, Via 8 Febbraio 2, 35122 Padova (Italy)

    2015-04-08

    The ITER neutral beam heating systems are based on the production and acceleration of negative ions (H/D) up to 1 MV. The requirements for the beam properties are strict: a low core beam divergence (< 0.4 °) together with a low source pressure (≤ 0.3 Pa) would permit to reduce the ion losses along the beamline, keeping the stripping particle losses below 30%. However, the attainment of such beam properties is not straightforward. At IPP, the negative ion source testbed BATMAN (BAvarian Test MAchine for Negative ions) allows for deepening the knowledge of the determination of the beam properties. One of the diagnostics routinely used to this purpose is the Beam Emission Spectroscopy (BES): the H{sub α} light emitted in the beam is detected and the corresponding spectra are evaluated to estimate the beam divergence and the stripping losses. The BES number of lines of sight in BATMAN has been recently increased: five horizontal lines of sight providing a vertical profile of the beam permit to characterize the negative ion beam properties in relation to the source parameters. Different methods of H{sub α} spectra analysis are here taken into account and compared for the estimation of the beam divergence and the amount of stripping. In particular, to thoroughly study the effect of the space charge compensation on the beam divergence, an additional hydrogen injection line has been added in the tank, which allows for setting different background pressure values (one order of magnitude, from about 0.04 Pa up to the source pressure) in the beam drift region.

  13. Modeling and control of thermostatically controlled loads

    OpenAIRE

    2011-01-01

    As the penetration of intermittent energy sources grows substantially, loads will be required to play an increasingly important role in compensating the fast time-scale fluctuations in generated power. Recent numerical modeling of thermostatically controlled loads (TCLs) has demonstrated that such load following is feasible, but analytical models that satisfactorily quantify the aggregate power consumption of a group of TCLs are desired to enable controller design. We develop such a model for...

  14. Adaptive rain fade compensation

    Science.gov (United States)

    Rautio, J. C.

    1980-01-01

    A large available margin must be provided for satellite communications systems operating near 20 GHz, which occasionally experience fades due to rain attenuation. It is proposed that this margin may be achieved in high-capacity FDMA satellites by dynamically providing a large margin to those links which are experiencing deep fades, while maintaining a small fade margin on all others. Single-beam SCPC operation and multiple-beam, satellite-switched FDMA systems are described, and the optimization of the dynamic FDMA links in a severely fading environment is investigated. A solution is derived which takes into account: (1) transponder intermodulation distortion, (2) cochannel and cross-polarization antenna interference, and (3) rain fade characteristics. The sample system configuration presented shows that such systems reach availability levels approaching 0.9999 at Ka-Band.

  15. DOL behaviour of end-notched beams

    DEFF Research Database (Denmark)

    Gustafsson, P.J.; Hoffmeyer, Preben; Valentin, G.

    1998-01-01

    The long-term loading strength of end-notched beams made of glulam and LVL was tested. The beams were of various sizes, with and without a moisture sealing at the notch. Tests were conducted in open shelter climates, and at constant and cyclic relative humidity. The short-term strength was tested...... beams with a moisture sealing at the notch...

  16. CLIC Drive Beam Phase Stabilisation

    CERN Document Server

    Gerbershagen, Alexander; Schulte, Daniel

    The thesis presents phase stability studies for the Compact Linear Collider (CLIC) and focuses in particular on CLIC Drive Beam longitudinal phase stabilisation. This topic constitutes one of the main feasibility challenges for CLIC construction and is an essential component of the current CLIC stabilisation campaign. The studies are divided into two large interrelated sections: the simulation studies for the CLIC Drive Beam stability, and measurements, data analysis and simulations of the CLIC Test Facility (CTF3) Drive Beam phase errors. A dedicated software tool has been developed for a step-by-step analysis of the error propagation through the CLIC Drive Beam. It uses realistic RF potential and beam loading amplitude functions for the Drive and Main Beam accelerating structures, complete models of the recombination scheme and compressor chicane as well as of further CLIC Drive Beam modules. The tool has been tested extensively and its functionality has been verified. The phase error propagation at CLIC h...

  17. Compensation for Power Quality Improvement in Electric Arc Furnace with Considering Economic Index

    OpenAIRE

    2012-01-01

    In recent years, on the one hand with increasing application of nonlinear loads in power systems and no sinusoidal currents that extracted from system, and on the other hand increasing loads sensitive to power quality and destructive effects of nonlinear loads on power quality of power systems, compensation these loads has been converted to one of the main issues in power systems. The use of flexible AC transmission system (FACTS) devices is one of the most progressive methods which are used ...

  18. Pulsed electron beam precharger

    Energy Technology Data Exchange (ETDEWEB)

    Finney, W.C. (ed.); Shelton, W.N.

    1991-01-01

    Electron beam precharging of a high resistivity aerosol was successfully demonstrated during this reporting period (Quarters Five and Six). The initial E-beam particle precharging experiments completed this term were designed to confirm and extend some of the work performed under the previous contract. There are several reasons for doing this: (1) to re-establish a baseline performance criterion for comparison to other runs, (2) to test several recently upgraded or repaired subsystems, and (3) to improve upon the collection efficiency of the electron beam precipitator when testing precharging effectiveness with a very high resistivity, moderate-to-high concentration dust load. In addition, these shakedown runs were used to determine a set of suitable operational parameters for the wind tunnel, the electrostatic collecting sections, and the MINACC E-beam accelerator. These parameters will generally be held constant while the precharging parameters are varied to produce an optimum particle charge.

  19. Combination of Reactive Current Droop Compensation and Line Drop Compensation for Improving Voltage Stability

    Institute of Scientific and Technical Information of China (English)

    TIAN Qing; LIN Xiang-ning

    2009-01-01

    Recent events related to power system failure have shown that voltage collapse can be a cause of widespread outages.The thrust of this paper is to discuss and establish means of mitigating system voltage instability by using a combination of both reactive current droop compensation and line drop compensation.It is shown that the point that the voltage regulator controls can be defined by a new method which is based on a widely accepted vohage stability analysis tool.This tool can be used to determine which generators will have an impact on the maximum permissible loading of a bus.Dynamic analysis was carried out on the CIGRE Nordic test system to study the impact of control point location on time to collapse and it is shown that the new scheme can improve the voltage stability.

  20. A 10 MHz ripple-based on-time controlled buck converter with dual ripple compensation

    Institute of Scientific and Technical Information of China (English)

    Lü Danzhu; Yu Jiale; Hong Zhiliang

    2013-01-01

    A 10 MHz ripple-based on-time controlled buck converter is presented.A novel low-cost dual ripple compensation,which consists of coupling capacitor compensation and passive equivalent series resistance compensation,is proposed to achieve a fast load transient response and robust stability simultaneously.Implemented in a 2P4M 0.35 μm CMOS process,the converter achieves fix-frequency output with a ripple of below 10 mV and an overshoot of 10 mV at 400 mA step load transient response.With width optimization of the power transistors in an ultra-heavy load and PFM control in a light load,the efficiency stays at over 83% for a load range from 20 mA to 1.5 A and the peak efficiency reaches 90.16%.

  1. SU-E-T-357: Electronic Compensation Technique to Deliver Total Body Dose

    Energy Technology Data Exchange (ETDEWEB)

    Lakeman, T [State University of New York at Buffalo, Buffalo, NY (United States); Wang, I; Podgorsak, M [State University of New York at Buffalo, Buffalo, NY (United States); Roswell Park Cancer Institute, Buffalo, NY (United States)

    2015-06-15

    Purpose: Total body irradiation (TBI) uses large parallel-opposed radiation fields to suppress the patient’s immune system and eradicate the residual cancer cells in preparation of recipient for bone marrow transplant. The manual placement of lead compensators has conventionally been used to compensate for the varying thickness through the entire body in large-field TBI. The goal of this study is to pursue utilizing the modern electronic compensation technique to more accurately and efficiently deliver dose to patients in need of TBI. Methods: Treatment plans utilizing electronic compensation to deliver a total body dose were created retrospectively for patients for whom CT data had been previously acquired. Each treatment plan includes two, specifically weighted, pair of opposed fields. One pair of open, large fields (collimator=45°), to encompass the patient’s entire anatomy, and one pair of smaller fields (collimator=0°) focused only on the thicker midsection of the patient. The optimal fluence for each one of the smaller fields was calculated at a patient specific penetration depth. Irregular surface compensators provide a more uniform dose distribution within the smaller opposed fields. Results: Dose-volume histograms (DVH) were calculated for the evaluating the electronic compensation technique. In one case, the maximum body doses calculated from the DVH were reduced from the non-compensated 195.8% to 165.3% in the electronically compensated plans, indicating a more uniform dose with the region of electronic compensation. The mean body doses calculated from the DVH were also reduced from the non-compensated 120.6% to 112.7% in the electronically compensated plans, indicating a more accurate delivery of the prescription dose. All calculated monitor units were well within clinically acceptable limits. Conclusion: Electronic compensation technique for TBI will not substantially increase the beam on time while it can significantly reduce the compensator

  2. Compensation: The Impact of Policy.

    Science.gov (United States)

    Morrell, Louis R.

    1994-01-01

    Complexity of employee compensation policy is examined as it applies to colleges and universities. It is argued that sound compensation policy helps the institution attract and retain qualified, skilled employees. New approaches that shift the focus from job to employee are outlined, and their implications for institutions of higher education are…

  3. Alternative Teacher Compensation: A Primer

    Science.gov (United States)

    Koppich, Julia E.; Rigby, Jessica

    2009-01-01

    This policy primer is designed to provide base-line information about new forms of teacher pay that are emerging around the country, to support the local conversations and negotiations that will lead to the development of innovative compensation systems. It identifies reasons why teacher compensation is high on local, state, and federal policy…

  4. An efficient dose-compensation method for proximity effect correction

    Energy Technology Data Exchange (ETDEWEB)

    Wang Ying; Han Weihua; Yang Xiang; Zhang Yang; Yang Fuhua [Research Center of Semiconductor Integrated Technology, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Zhang Renping, E-mail: wangying@semi.ac.c [State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    2010-08-15

    A novel simple dose-compensation method is developed for proximity effect correction in electron-beam lithography. The sizes of exposed patterns depend on dose factors while other exposure parameters (including accelerate voltage, resist thickness, exposing step size, substrate material, and so on) remain constant. This method is based on two reasonable assumptions in the evaluation of the compensated dose factor: one is that the relation between dose factors and circle-diameters is linear in the range under consideration; the other is that the compensated dose factor is only affected by the nearest neighbors for simplicity. Four-layer-hexagon photonic crystal structures were fabricated as test patterns to demonstrate this method. Compared to the uncorrected structures, the homogeneity of the corrected hole-size in photonic crystal structures was clearly improved. (semiconductor technology)

  5. Hierarchical Control Scheme for Voltage Unbalance Compensation in Islanded Microgrids

    DEFF Research Database (Denmark)

    Savaghebi, Mehdi; Guerrero, Josep M.; Jalilian, Alireza;

    2011-01-01

    active and reactive power controllers, virtual impedance loop and voltage and current controllers. The secondary level is designed to compensate the voltage unbalance at the load bus (LB) of the islanded microgrid. Also, restoration of LB voltage amplitude and microgrid frequency to the rated values...... is considered in the secondary level. These functions are achieved by proper control of distributed generators (DGs) interface converters. The presented simulation results show the effectiveness of the proposed control structure in compensating the voltage unbalance and restoring the voltage amplitude...

  6. 38 CFR 3.459 - Death compensation.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Death compensation. 3.459..., Compensation, and Dependency and Indemnity Compensation Apportionments § 3.459 Death compensation. (a) Death compensation will be apportioned if the child or children of the deceased veteran are not in the custody of...

  7. Workers' compensation law: an overview.

    Science.gov (United States)

    Yorker, B

    1994-09-01

    1. The workers' compensation system provides benefits to workers who are injured or made ill in the course of employment or their dependents regardless of fault. 2. The current workers' compensation laws benefit both the employer and the employee; however, workers' compensation is an exclusive remedy which bars recovery through a negligence lawsuit. 3. Workers' compensation regulations interact with other federal statutes such as the Americans With Disabilities Act and the Family Medical Leave Act. 4. Workers' compensation covers occupational injuries and occupational diseases, which may include cumulative trauma and mental stress claims. Nurses may be instrumental in evaluating and planning for an injured employee's return to work and occasionally in detecting fraudulent claims.

  8. Load Measurements

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    The report describes Load measurements carried out on a given wind turbine. The aim of the measurement program regarding the loads on the turbine is to verify the basic characteristics of the wind turbine and loads on the blades, the rotor and the tower, using [Ref 1], [Ref2] and [Ref 3]. Regarding...... the fatigue loads, the rotor, blades and tower moments are presented. The fatigue loads are evaluated using rainflow counting described in detail in Ref. [1]. The 1Hz equivalent load ranges are calculated at different wind speeds. All information regarding the instrumentation is collected in [ref 4] and [ref...

  9. System overview on electromagnetic compensation for reflector antenna surface distortion

    Science.gov (United States)

    Acosta, R. J.; Zaman, A. J.; Terry, J. D.

    1993-01-01

    The system requirements and hardware implementation for electromagnetic compensation of antenna performance degradations due to thermal effects was investigated. Future commercial space communication antenna systems will utilize the 20/30 GHz frequency spectrum and support very narrow multiple beams (0.3 deg) over wide angle field of view (15-20 beamwidth). On the ground, portable and inexpensive very small aperture terminals (VSAT) for transmitting and receiving video, facsimile and data will be employed. These types of communication system puts a very stringent requirement on spacecraft antenna beam pointing stability (less than .01 deg), high gain (greater than 50 dB) and very lowside lobes (less than -25 dB). Thermal analysis performed on the advanced communication technology satellite (ACTS) has shown that the reflector surfaces, the mechanical supporting structures and metallic surfaces on the spacecraft body will distort due thermal effects from a varying solar flux. The antenna performance characteristics (e.g., pointing stability, gain, side lobe, etc.) will degrade due to thermal distortion in the reflector surface and supporting structures. Specifically, antenna RF radiation analysis has shown that pointing error is the most sensitive antenna performance parameter to thermal distortions. Other antenna parameters like peak gain, cross polarization level (beam isolation), and side lobe level will also degrade with thermal distortions. In order to restore pointing stability and in general antenna performance several compensation methods were proposed. In general these compensation methods can be classified as being either of mechanical or electromagnetic type. This paper will address only the later one. In this approach an adaptive phased array antenna feed is used to compensate for the antenna performance degradation. Extensive work has been devoted to demonstrate the feasibility of adaptive feed compensation on space communication antenna systems. This

  10. Thin lead sheets as tissue compensators for larger field irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, K.P.; Baxter, D.H.; Ray, P.

    1980-04-01

    This paper describes the use of a thin lead sheet as a tissue compensating filter when a large field that includes the supraclavicular and mediastinal regions is irradiated. The typical midplane depths between supraclavicular and mediastinal regions may vary between 6 to 12 cm. Flattening of the beam entry surface is necessary for dose uniformity; this is achieved with a thin lead sheet compensating filter on the shadow tray of a 4 MV Unit. The shadow tray also contains lead shielding blocks for lung, cervical spinal cord, and larynx. The advantages of using thin lead sheets include easy maneuverability of shaping and sizing for irregular fields, and the small dimensions that are needed. Dose uniformity is verified by measuring optical densities from the film that is taken with the actual tray containing this compensating filter. This compensating filter may be extended to many situations where there are marked dose variations between different locations within the same large radiation field. The electron contamination produced by the scattering medium being placed in the beam is less for lead than for aluminum and wax. This contamination is also insignificant when the scatterer is more than 20 cm. away from the patient's skin surface when Cobalt-60 and 4 MV units are used.

  11. Experience with Advanced Static VAR Compensators Operating on Wind Farms and in Laboratory in Denmark

    DEFF Research Database (Denmark)

    Pedersen, Jørgen Kaas; Pedersen, Knud Ole Helgesen; Rasmussen, Tonny Wederberg

    1999-01-01

    Wind turbines with induction generators consume reactive power. Apart from the no-load consumption that is almost constant, the consumption of reactive power varies almost in proportion with the power production, which can vary immensely. Apart from the fact that the grid must supply the reactive....... This paper describes a 100 kvar power electronic reactive power compensator. The compensator was tested in a wind farm in Western Denmark. The electrical circuit and the working principle of the compensator are described and some survey data are shown. The paper also describes a 2x4 Mvar reactive power...... compensator placed in another wind farm of a total of 24 WM in Western Denmark with the aim to compensate the whole farm. Measurements of operation and losses are given. Finally the paper describes a new control strategy tested on a 10 kvar multilevel reactive power compensator....

  12. The refined theory of transversely isotropic piezoelectric rectangular beams

    Institute of Scientific and Technical Information of China (English)

    GAO; Yang; WANG; Minzhong

    2006-01-01

    The problem of deducing one-dimensional theory from two-dimensional theory for a transversely isotropic piezoelectric rectangular beam is investigated. Based on the piezoelasticity theory, the refined theory of piezoelectric beams is derived by using the general solution of transversely isotropic piezoelasticity and Lur'e method without ad hoc assumptions. Based on the refined theory of piezoelectric beams, the exact equations for the beams without transverse surface loadings are derived, which consist of two governing differential equations: the fourth-order equation and the transcendental equation. The approximate equations for the beams under transverse loadings are derived directly from the refined beam theory. As a special case, the governing differential equations for transversely isotropic elastic beams are obtained from the corresponding equations of piezoelectric beams. To illustrate the application of the beam theory developed, a uniformly loaded and simply supported piezoelectric beam is examined.

  13. Modeling and Simulation of Series Compensator to Mitigate Power Quality Problems

    Directory of Open Access Journals (Sweden)

    S.Sadaiappan,

    2010-12-01

    Full Text Available Power Electronics and Advanced Control technologies have made it possible to mitigate power quality problems and maintain the operation of sensitive loads. Among power system disturbances, voltage sags, swells and harmonics are some of the severe problems to the sensitive loads. The series compensation method is best suited to protect such loads against those disturbances. The use of a series compensator (SC to improve power quality is an isolated power system is investigated. The role of the compensator is not only to mitigate the effects of voltage sag, but also to reduce the harmonic distortion due to the presence of non linear loads in the network. In this paper, a series compensator is proposed and a method of harmonic compensation is described and a method to mitigate voltage sag is investigated. The proposed series compensator consists of Energy Storage System (ESS and Voltage Source Inverter (VSI, Injection Transformer. The ESS can be a capacitor of suitable capacity. ESS would act as a buffer and generally provides the energy needed for load ride-through during voltage sag. Injection Transformer is used to inject the voltage in transmission line in appropriate level.In this way the terminal voltage of the protected sensitive load can be regulated to maintain a constant level. The modeling and imulation of the proposed series compensator was implemented in Matlab Simulink work space. Simulation results showed that the proposed series compensator was efficient in mitigating voltage sags and harmonics and thus improve the power quality of the isolated power system. This approach is different from conventional methods and provides effective solution. If this method is enhanced in future it could provide much more improved power quality.

  14. Analyzing of Dynamic Voltage Restorer in Series Compensation Voltage

    Directory of Open Access Journals (Sweden)

    Naser Parhizgar

    2012-02-01

    Full Text Available The Dynamic Voltage Restorer (DVR is a series-connected compensator to generate a controllable voltage to against the short-term voltage disturbances. The technique of DVR is an effective and cost competitive approach to improve voltage quality at the load side. This study presents a single-phase and threephase DVR system with reduced switch-count topology to protect the sensitive load against abnormal voltage conditions. Most basic function, the DVR configuration consist of a two level Voltage Source Converter (VSC, a dc energy storage device, a coupling transformer Connected in shunt with the ac system This study presents the application of Dynamic Voltage Restorer (DVR on power distribution systems for mitigation of voltage sag at critical loads. DVR is one of the compensating types of custom power devices. The DVR, which is based on forced-commutated Voltage Source Converter (VSC has been proved suitable for the task of compensating voltage sags/swells. Simulation results are presented to illustrate and understand the performances of DVR in supporting load voltages under voltage sags/swells conditions.

  15. Four-Wire Delta Service Sinusoidal Operation and Compensation Simulator

    Directory of Open Access Journals (Sweden)

    Vicente León-Martínez

    2015-10-01

    Full Text Available An off-line simulator based on Excel used to evaluate the operation of four-wire delta (4WD services as well as the effects of reactive and imbalance compensators in sinusoidal steady-state conditions is described in this paper. Voltages, currents and powers in the primary and secondary windings of the transformer as well as in the high voltage (HV and low voltage (LV lines and in the loads are calculated through that simulator. The apparent powers in the mains, transformer and loads are determined applying Buchholz’s and unified power measurement (UPM formulations in both scalar and vector notations. The effects of the neutral current are especially examined, in order to minimize them, and the optimal wye load distribution is determined by the simulator. The simulator provides the necessary elements of passive reactive and unbalanced compensators that optimize the 4WD transformer operation too. Those compensators are determined for each load, and they can be separately selected and included in the simulation process or not. An application example is finally used to step by step explain how the simulator runs.

  16. Load Measurements

    DEFF Research Database (Denmark)

    Vesth, Allan; Kock, Carsten Weber

    The report describes Load measurements carried out on a given wind turbine. The aim of the measurement program regarding the loads on the turbine is to verify the basic characteristics of the wind turbine and loads on the blades, the rotor and the tower, using [Ref 1], [Ref2] and [Ref 3]. Regardi...

  17. 碳纤维加固钢-混凝土组合梁承载力极限状态计算%Analysis of Ultimate Load-carrying Capacity of Strengthening Steel-concrete Composite Beam Using Carbon Fiber

    Institute of Scientific and Technical Information of China (English)

    荣学亮; 黄侨

    2011-01-01

    Carbon fiber is a kind of optimal materials for bridge maintenance and reinforcement. Design method of strengthening steel-concrete composite bridges using carbon fiber was studied. Characteristic of bridge reinforce-ment under load and phasing of stress features were considered, and calculation method of ultimate limit state was suitable for existing bridge design code . Ultimate strain of carbon fiber in ultimate limit state is firstly established based on plane-section assumption and strain-lag of carbon fiber. Then computational scheme and calculation meth-od of flexural capacity in positive moment area and negative moment area for strengthening steel-concrete composite beam using carbon fiber are established respectively, which is reference for design of bridge strengthening.%碳纤维复合材料是进行桥梁维修和加固的理想材料.对采用碳纤维复合材料加固钢-混凝土组合梁桥的设计方法进行了分析.考虑桥梁结构带载加固分阶段受力的特点,与现行桥梁设计规范中承载能力极限状态计算方法相适应.首先基于平截面假设和碳纤维应变滞后的特点,确定承载能力极限状态下碳纤维片材的极限应变值.然后分别建立了碳纤维片材加固钢-混凝土组合梁在正弯矩区和负弯矩区抗弯承载力的计算图式和计算方法,可供桥梁加固工程设计参考.

  18. Dynamically loaded beam failure under corroded conditions

    NARCIS (Netherlands)

    Veerman, R.P.; Koenders, E.A.B.

    2014-01-01

    De-icing salts, used on roads in heavy winters, may enter reinforced concrete (RC) structures via its capillary pore system or via cracks, initiating reinforcement corrosion and reducing its remaining service-life. Vehicles passing real bridges exert a dynamic impact action that might activate a fat

  19. Evaluation of photomask flatness compensation for extreme ultraviolet lithography

    Science.gov (United States)

    Ballman, Katherine; Lee, Christopher; Zimmerman, John; Dunn, Thomas; Bean, Alexander

    2016-10-01

    As the semiconductor industry continues to strive towards high volume manufacturing for EUV, flatness specifications for photomasks have decreased to below 10nm for 2018 production, however the current champion masks being produced report P-V flatness values of roughly 50nm. Write compensation presents the promising opportunity to mitigate pattern placement errors through the use of geometrically adjusted target patterns which counteract the reticle's flatness induced distortions and address the differences in chucking mechanisms between e-beam write and electrostatic clamping during scan. Compensation relies on high accuracy flatness data which provides the critical topographical components of the reticle to the write tool. Any errors included in the flatness data file are translated to the pattern during the write process, which has now driven flatness measurement tools to target a 6σ reproducibility write compensation is validated against printed wafer results. Topographic features which lack compensation capability must then be held to stringent specifications in order to limit their contributions to the final image placement error (IPE) at wafer. By understanding the capabilities and limitations of write compensation, it is then possible to shift flatness requirements towards the "non-correctable" portion of the reticle's profile, potentially relieving polishers from having to adhere to the current single digit flatness specifications.

  20. Cyclodissipativity and Power Factor Improvement for Full Nonlinear Loads

    NARCIS (Netherlands)

    Puerto-Flores, Dunstano del; Ortega, Romeo; Scherpen, Jacquelien M.A.; Edelmayer, András

    2010-01-01

    In recent research, a cyclodissipativity characterization of the problem of power factor compensation (PFC) for nonlinear loads with non-sinusoidal source voltage has been presented. Using this characterization the classical capacitor and inductor compensators can be interpreted in terms of energy e

  1. Wavefront Compensation Segmented Mirror Sensing and Control

    Science.gov (United States)

    Redding, David C.; Lou, John Z.; Kissil, Andrew; Bradford, Charles M.; Woody, David; Padin, Stephen

    2012-01-01

    The primary mirror of very large submillimeter-wave telescopes will necessarily be segmented into many separate mirror panels. These panels must be continuously co-phased to keep the telescope wavefront error less than a small fraction of a wavelength, to ten microns RMS (root mean square) or less. This performance must be maintained continuously across the full aperture of the telescope, in all pointing conditions, and in a variable thermal environment. A wavefront compensation segmented mirror sensing and control system, consisting of optical edge sensors, Wavefront Compensation Estimator/Controller Soft ware, and segment position actuators is proposed. Optical edge sensors are placed two per each segment-to-segment edge to continuously measure changes in segment state. Segment position actuators (three per segment) are used to move the panels. A computer control system uses the edge sensor measurements to estimate the state of all of the segments and to predict the wavefront error; segment actuator commands are computed that minimize the wavefront error. Translational or rotational motions of one segment relative to the other cause lateral displacement of the light beam, which is measured by the imaging sensor. For high accuracy, the collimator uses a shaped mask, such as one or more slits, so that the light beam forms a pattern on the sensor that permits sensing accuracy of better than 0.1 micron in two axes: in the z or local surface normal direction, and in the y direction parallel to the mirror surface and perpendicular to the beam direction. Using a co-aligned pair of sensors, with the location of the detector and collimated light source interchanged, four degrees of freedom can be sensed: transverse x and y displacements, as well as two bending angles (pitch and yaw). In this approach, each optical edge sensor head has a collimator and an imager, placing one sensor head on each side of a segment gap, with two parallel light beams crossing the gap. Two sets

  2. Review of Static Compensation of Autonomous Systems

    Directory of Open Access Journals (Sweden)

    Ambarnath Banerji

    2012-01-01

    Full Text Available Abstract Deregulation of the electric power energy market has thrown open opportunities for tapping the large number of small pockets of renewable energy sources with the asynchronous generators. Whether the power is supplied by asynchronous generator or by the grid at the remote location, its quality has become an important aspect for consumers of electricity. Efforts have been made to improve the power quality using passive filters, active filters and the new concept of Custom Power. Use of Custom power devices ensures that a load do not pollute the power supply of the other loads. One such custom power device is the DSTATCOM (Distribution Static Compensator which is connected in shunt at the load end. The heart of the DSTATCOM is an inverter. The focus on the autonomous generation has increased in the recent years. The paper presents a comprehensive review of the DSTATCOM used for autonomous generation. It is aimed at providing a broad perspective on the status of DSTATCOM, used with Asynchronous generators, vis-à-vis its working principle, topology, solid state switching devices and technology, supply system, control methodologies and approaches, technical and economic considerations, etc. to researchers and application engineers dealing with power quality aspects of Autonomous Systems. Classified manner in which the references are presented in this paper will serve them as quick and useful reference.

  3. Stock Repurchases and Incentive Compensation

    OpenAIRE

    Christine Jolls

    1998-01-01

    A longstanding puzzle in corporate finance is the rise of stock repurchases as a means of distributing earnings to shareholders. While most attempts to explain repurchase behavior focus on the incentives of firms, this paper focuses on the incentives of the agents who run firms, as determined by those agents' compensation packages. The increased use of repurchases coincided with an increasing reliance on stock options to compensate top managers, and stock options encourage managers to choose ...

  4. Synchronous compensators for mini-grids and islanding: final report

    Energy Technology Data Exchange (ETDEWEB)

    Thornycroft, J.; Caisley, A.; Russell, T.; Willis, S.; Youssef, R.; Bawden, R.; Holden, G.; Williams, J.

    2004-07-01

    This report presents the findings of a project to develop equipment suitable for the operation of islanded induction generator wind turbines in remote areas with voltage control supplied by synchronous compensators and frequency control supplied by distributed intelligent load controllers. The development of a design methodology for stand-alone wind turbines systems is described, and details are given of its application to the construction of a 25kw Gazelle wind turbine in Sunderland and a 300kW Windmaster wind turbine in Northumberland. Both systems were islanded from the electric grid and fitted with synchronous compensators and distributed intelligent load controllers. The work carried out is listed, and design considerations, system simulation, and the data logging systems are discussed.

  5. Unified Power Quality Conditioner for voltage and current compensation

    Directory of Open Access Journals (Sweden)

    P.Annapandi

    2012-07-01

    Full Text Available This paper deals with a Unified Power Quality Conditioner (UPQC for load balancing, power factorcorrection, voltage regulation, voltage and current harmonics mitigation, mitigation of voltage sag, swelland voltage dip in a three-phase three-wire distribution system for different combinations of linear and nonlinear loads.The unified power quality conditioner (UPQC is a combination of back to back connected shunt and series active power filters (APFs to a common DC link voltage, which compensates voltage and current based distortions, independently.Using instantaneous active and reactive Power theory ,harmonic detection, reactive power compensation, voltage sag and swell have been simulated and the results are analyzed. The operation and capability of the proposed system was analyzed through simulations with MATLAB / SIMULINK.

  6. Creep Effects in Pultruded FRP Beams

    Science.gov (United States)

    Boscato, G.; Casalegno, C.; Russo, S.

    2016-03-01

    The paper presents results of two creep tests on pultruded open-section GFRP beams aimed to evaluate the long-term deformations, the residual deflection after unloading, and the influence of creep strains on the flexuraltorsional buckling phenomenon. Two beams were subjected to a constant load for about one year. Then one of the beams was unloaded to evaluate its residual deflection. For the other beam, the load was increased up to failure, and the residual buckling strength was compared with that of a similar beam tested up to failure. The parameters of the Findley power law are evaluated, and the experimental results are compared with those of numerical analyses and with available formulations for prediction of the time-dependent properties of composite beams. Results of the investigation testify, in particular, to a noninsignificant time-dependent increment in deflections of the beams and to a significant reduction in their buckling strength due to creep deformations.

  7. Radiobiological compensation: A case study of uterine cervix cancer with concurrent chemotherapy

    Science.gov (United States)

    Herrera, Higmar; Yañez, Elvia; López, Jesús

    2012-10-01

    The case of a patient diagnosed with uterine cervix cancer is presented as an example of the clinical application of the radiobiological compensation method implemented at Centro Estatal de Cancerología de Durango. Radiotherapy treatment was initially modified to compensate for the chemotherapy component and, as medical complications arose during treatment delivery resulting in an 18 days gap, new compensation followed. All physical and radiobiological assumptions to calculate the Biologically Effective Dose in the external beam and brachytherapy parts of the treatment are presented. Good local control of the tumor was achieved, the theoretical tolerance limits for the organs at risk were not surpassed and the patient manifested no extensive morbidity.

  8. Transverse momentum compensation in [pi][sup +]p interactions at 250 GeV/c

    Energy Technology Data Exchange (ETDEWEB)

    Agababyan, N.M.; Ajinenko, I.V.; Bialkowska, H.; Chliapnikov, P.V.; Botterweck, F.; Charlet, M.; Wolf, E.A. de; Dziunikowska, K.; Endler, A.M.F.; Garutchava, Z.C.; Gulkanyan, H.R.; Kisielewska, D.; Kittel, W.; Olkiewicz, K.; Rizatdinova, F.K.; Shabalina, E.K.; Smirnova, L.N.; Stepaniak, J.; Tikhonova, L.A.; Tomaradze, A.G.; Wroblewski, A.; Verbeure, F.; Zotkin, S.A. (Dept. of Physics, Univ. Instelling Antwerpen, Wilrijk (Belgium) Inter-Univ. Inst. for High Energies, Brussels (Belgium) Inst. of Physics and Nuclear Techniques of Academy of Mining and Metallurgy and Inst. of Nuclear Physics, Krakow (Poland) Nuclear Physics Inst., Moscow State Univ. (Russian Federation) Univ. of Nijmegen/NIKHEF (Netherlands) Inst. for High Energy Physics, Protvino (Russian Federation) Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, RJ (Brazil) Inst. of High Energy Physics of Tbilisi State Univ. (Georgia) Univ. of Warsaw and Inst. for Nuclear Studies, Warsaw (Poland) Inst. of Physics, Yerevan (Arme; EHS/NA22 Collaboration

    1994-11-01

    Compensation of transverse momentum is studied in [pi][sup +] p interactions at 250 GeV/c. Significant p[sub T]-transfer is found between c.m.s. hemispheres. With respect to the beam axis transverse momentum is compensated over the whole event, with respect to the sphericity axis mainly within one hemisphere. The highest p[sub T] in the event is mainly compensated by increased multiplicity. The QGSM and FRITIOF models qualitatively reproduce these effects, but important differences are observed. (orig.)

  9. Radiobiological compensation: A case study of uterine cervix cancer with concurrent chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, Higmar; Yanez, Elvia; Lopez, Jesus [Centro Estatal de Cancerologia de Durango, Victoria de Durango, Durango (Mexico); ISSSTE General Hospital Dr. Santiago Ramon y Cajal, Victoria de Durango, Durango (Mexico)

    2012-10-23

    The case of a patient diagnosed with uterine cervix cancer is presented as an example of the clinical application of the radiobiological compensation method implemented at Centro Estatal de Cancerologia de Durango. Radiotherapy treatment was initially modified to compensate for the chemotherapy component and, as medical complications arose during treatment delivery resulting in an 18 days gap, new compensation followed. All physical and radiobiological assumptions to calculate the Biologically Effective Dose in the external beam and brachytherapy parts of the treatment are presented. Good local control of the tumor was achieved, the theoretical tolerance limits for the organs at risk were not surpassed and the patient manifested no extensive morbidity.

  10. Dynamic loads in the glove machine due to the carriages reciprocating motion and the dynamic load reduction

    Directory of Open Access Journals (Sweden)

    Vitaliy V. Chaban

    2014-12-01

    Full Text Available This research is devoted to analyzing the dynamic loads generated in the glove machine at reciprocating motion of knitting and intermediate carriages. Proposed is a method for determining the maximum dynamic loads in the glove machine carriages’ drive. It is noted that the dynamic loads reduction can be achieved by equipping the drive with energy accumulation and compensation units, in which quality it is expedient to use the cylindrical compression springs. The obtained dependence allows to determine the necessary stiffness of compression springs (energy accumulating and compensating units, at which the dynamic loads due to the carriages masses’ inertia can be almost completely eliminated.

  11. Extreme long range process effects characterization and compensation

    Science.gov (United States)

    Figueiro, Thiago; Browning, Clyde; Thornton, Martin J.; Vannuffel, Cyril; Choi, Kang-Hoon; Hohle, Christoph; Tortai, Jean-Herve; Schiavone, Patrick

    2013-10-01

    Proximity Effects in electron beam lithography impact feature dimensions, pattern fidelity and uniformity. These effects are addressed using a mathematical model representing the radial exposure intensity distribution induced by a point electron source, commonly named as the Point Spread Function (PSF). PSF models are usually employed for predicting and compensating for effects up to 15μm. It is well known that there are also some process related phenomena that impact pattern uniformity that have a longer range, namely CMP effects, fogging, etc. Performing proximity effects corrections can result in lengthy run times as file size and pattern densities continue to increase exponentially per technology node. Running corrections for extreme long range phenomena becomes computational and file size prohibitive. Nevertheless, since extreme long range may reach up several millimeters, and new technology nodes require a high level of precision, a strategy for predicting and compensating these phenomena is crucial. In this paper a set of test patterns are presented in order to verify and calibrate the so called extreme long range effects in the electron beam lithography. Moreover, a strategy to compensate for extreme long range effects based on the pattern density is presented. Since the evaluation is based on a density map instead of the actual patterns, the computational effort is feasible. The proposed method may be performed off-line (in contrast to machine standard in-line correction). The advantage of employing off-line compensation relies on enhancing the employ of dose and/or geometry modulation. This strategy also has the advantage of being completely decoupled from other e-beam writer's internal corrections (like Fogging Effect Correction - FEC).

  12. An Eigenstructure Assignment for a Static Synchronous Compensator

    Directory of Open Access Journals (Sweden)

    Ahmad N. Al-Husban

    2009-01-01

    set of eigenvalues was obtained. It improves the overall system performance and yields a class of controllers contributing uniformly to the assignment process. The voltage could be kept constant independent of the loads with static compensator. The results show clearly the applicability of the proposed control scheme which is acceptable for the static compensator.

  13. Power factor compensation with lossless linear filters is equivalent to (weighted) power equalization and a new cyclo–dissipativity characterization

    NARCIS (Netherlands)

    Puerto-Flores, Dunstano del; Ortega, Romeo; Scherpen, Jacquelien M.A.

    2009-01-01

    Recently, it has been established that the problem of power factor compensation for nonlinear loads with non-sinusoidal source voltage can be recast in terms of the property of cyclo–dissipativity. Using this framework the classical capacitor and inductor compensators can be interpreted in terms of

  14. 14 CFR 158.53 - Collection compensation.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Collection compensation. 158.53 Section 158... Collection compensation. (a) As compensation for collecting, handling, and remitting the PFC revenue, the... a new compensation level based on an analysis of the data provided under paragraph (c)(1) of...

  15. 48 CFR 752.7007 - Personnel compensation.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Personnel compensation... Personnel compensation. The following clause shall be used in all USAID cost-reimbursement contracts. Personnel Compensation (JUL 2007) (a) Direct compensation of the Contractor's personnel will be...

  16. 22 CFR 96.34 - Compensation.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Compensation. 96.34 Section 96.34 Foreign... Financial and Risk Management § 96.34 Compensation. (a) The agency or person does not compensate any... for compensation within the intercountry adoption community in that country, to the extent that...

  17. 30 CFR 90.103 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compensation. 90.103 Section 90.103 Mineral..., Rights of Part 90 Miners § 90.103 Compensation. (a) The operator shall compensate each Part 90 miner at... part. (d) In addition to the compensation required to be paid under paragraphs (a), (b) and (c) of...

  18. 48 CFR 970.2270 - Unemployment compensation.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Unemployment compensation... Unemployment compensation. (a) Each state has its own unemployment compensation system to provide payments to... unemployment compensation benefits through a payroll tax on employers. Most DOE contractors are subject to...

  19. 43 CFR 4.355 - Omitted compensation.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Omitted compensation. 4.355 Section 4.355... Compensation § 4.355 Omitted compensation. When, subsequent to the issuance of a final order determining heirs under § 4.352, it is found that certain additional compensation had been due the decedent and had...

  20. 7 CFR 930.133 - Compensation rate.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Compensation rate. 930.133 Section 930.133 Agriculture... Regulations § 930.133 Compensation rate. A compensation rate of $250 per meeting shall be paid to the public member and to the alternate public member when attending Board meetings. Such compensation is a...

  1. 12 CFR 9.15 - Fiduciary compensation.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Fiduciary compensation. 9.15 Section 9.15 Banks... BANKS Regulations § 9.15 Fiduciary compensation. (a) Compensation of bank. If the amount of a national bank's compensation for acting in a fiduciary capacity is not set or governed by applicable law,...

  2. 23 CFR 751.15 - Just compensation.

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Just compensation. 751.15 Section 751.15 Highways... AND ACQUISITION § 751.15 Just compensation. (a) Just compensation shall be paid the owner for the... removed, relocated, or disposed of pursuant to 23 U.S.C. 136. (b) No rights to compensation accrue until...

  3. 12 CFR 7.2011 - Compensation plans.

    Science.gov (United States)

    2010-01-01

    ... Corporate Practices § 7.2011 Compensation plans. Consistent with safe and sound banking practices and the compensation provisions of 12 CFR part 30, a national bank may adopt compensation plans, including, among... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Compensation plans. 7.2011 Section 7.2011...

  4. 29 CFR 525.6 - Compensable time.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Compensable time. 525.6 Section 525.6 Labor Regulations... WITH DISABILITIES UNDER SPECIAL CERTIFICATES § 525.6 Compensable time. Individuals employed subject to this part must be compensated for all hours worked. Compensable time includes not only those...

  5. Theoretical analysis of some problems in the measurement of beam divergence angle for EAST neutral beam injector

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Beam angular divergence is one of the indicators to evaluate the beam quality. Operating parameters of the beam extraction system could be adjusted to gain better beam quality following the measurement results, which will be helpful not only to study the transmission characteristics of the beam and the power distribution on the heat load components, but also to understand the real-time working condition of the ion source and beam extraction system. This study includes: (1) the theoretical analysis of beam extraction pulse duration for measurement of beam angular divergence; (2) the theoretical analysis of beam intensity distribution during beam transmission for Experimental Advanced Superconducting Tokomak (EAST) neutral beam injector. Those theoretical analyses could point the way to the measurement of beam divergence angle for EAST neutral beam injector.

  6. 75 FR 49595 - Performance of Functions; Claims for Compensation Under the Federal Employees' Compensation Act...

    Science.gov (United States)

    2010-08-13

    ... Labor Office of Workers' Compensation Programs 20 CFR Parts 1, 10, and 25 Performance of Functions; Claims for Compensation Under the Federal Employees' Compensation Act; Compensation for Disability and... Workers' Compensation Programs 20 CFR Parts 1, 10, and 25 RIN 1240-AA03 Performance of Functions;...

  7. ICFA Beam Dynamics Newsletter

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi I.; Kuczewski A.; Altinbas, Z.; Beavis, D.; Belomestnykh,; Dai, J. et al

    2012-07-01

    The Collider-Accelerator Department at Brookhaven National Laboratory is building a high-brightness 500 mA capable Energy Recovery Linac (ERL) as one of its main R&D thrusts towards eRHIC, the polarized electron - hadron collider as an upgrade of the operating RHIC facility. The ERL is in final assembly stages, with injection commisioning starting in October 2012. The objective of this ERL is to serve as a platform for R&D into high current ERL, in particular issues of halo generation and control, Higher-Order Mode (HOM) issues, coherent emissions for the beam and high-brightness, high-power beam generation and preservation. The R&D ERL features a superconducting laser-photocathode RF gun with a high quantum efficiency photoccathode served with a load-lock cathode delivery system, a highly damped 5-cell accelerating cavity, a highly flexible single-pass loop and a comprehensive system of beam instrumentation. In this ICFA Beam Dynamics Newsletter article we will describe the ERL in a degree of detail that is not usually found in regular publications. We will discuss the various systems of the ERL, following the electrons from the photocathode to the beam dump, cover the control system, machine protection etc and summarize with the status of the ERL systems.

  8. Pulsed electron beam precharger

    Energy Technology Data Exchange (ETDEWEB)

    Finney, W.C. (ed.); Shelton, W.N.

    1990-01-01

    Electrostatic collection of a high resistivity aerosol using the Electron Beam Precipitator (EBP) collecting section was demonstrated during this reporting period (Quarter Five). Collection efficiency experiments were designed to confirm and extend some of the work performed under the previous contract. The reason for doing this was to attempt to improve upon the collection efficiency of the precipitator alone when testing with a very high resistivity, moderate-to-high concentration dust load. From the collector shakedown runs, a set of suitable operational parameters were determined for the downstream electrostatic collecting sections of the Electron Beam Precipitator wind tunnel. These parameters, along with those for the MINACC electron beam, will generally be held constant while the numerous precharging parameters are varied to produce an optimum particle charge. The electrostatic collector experiments were part of a larger, comprehensive investigation on electron beam precharging of high resistivity aerosol particles performed during the period covered by Quarters Five, Six, and Seven. This body of work used the same experimental apparatus and procedures and the experimental run period lasted nearly continuously for six months. A summary of the Quarter Five work is presented in the following paragraphs. Section II-A of TPR 5 contains a report on the continuing effort which was expended on the modification and upgrade of the pulsed power supply and the monitoring systems prior to the initiation of the electron beam precharging experimental work.

  9. Compensation of impedance meters when using an external front-end amplifier

    OpenAIRE

    Torrents Dolz, Josep M.; Pallàs Areny, Ramon

    2002-01-01

    Four-terminal impedance meters based on pseudo-bridges yield unexpected uncertainties when using high-contact-impedance electrodes. Adding a front-end amplifier to the impedance meter and rearranging the connection of the meter terminals overcome the contact impedance problem. However, because the compensation provisions in the instrument are meant to compensate only impedance residuals of test fixtures, by either an open/short or an open/short/load correction procedure, the external fr...

  10. Reactive Power Compensation and Harmonic Suppression for Power Supply System of HT-7U Superconductive Tokamak

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, a strategy for the reactive power compensation and harmonic suppression of the power supply system in HT-7U superconductive Tokamak is proposed. The optimizedapproach is given in the parameters design for passive filter. Also a controlling method with fastresponse time and good accuracy is put forward for the compensator, which is more suitable forthe dynamic load.PAGS: 84.70.+p ,52.55. Fa, 84.30. Vn

  11. Compensation for electrical converter nonlinearities

    Science.gov (United States)

    Perisic, Milun; Ransom, Ray M; Kajouke, Lateef A

    2013-11-19

    Systems and methods are provided for delivering energy from an input interface to an output interface. An electrical system includes an input interface, an output interface, an energy conversion module between the input interface and the output interface, an inductive element between the input interface and the energy conversion module, and a control module. The control module determines a compensated duty cycle control value for operating the energy conversion module to produce a desired voltage at the output interface and operates the energy conversion module to deliver energy to the output interface with a duty cycle that is influenced by the compensated duty cycle control value. The compensated duty cycle control value is influenced by the current through the inductive element and accounts for voltage across the switching elements of the energy conversion module.

  12. Electronic amplifiers for automatic compensators

    CERN Document Server

    Polonnikov, D Ye

    1965-01-01

    Electronic Amplifiers for Automatic Compensators presents the design and operation of electronic amplifiers for use in automatic control and measuring systems. This book is composed of eight chapters that consider the problems of constructing input and output circuits of amplifiers, suppression of interference and ensuring high sensitivity.This work begins with a survey of the operating principles of electronic amplifiers in automatic compensator systems. The succeeding chapters deal with circuit selection and the calculation and determination of the principal characteristics of amplifiers, as

  13. Depth Compensated Spectral Domain Optical Coherence Tomography via Digital Compensation

    CERN Document Server

    Boroomand, Ameneh; Shafiee, Mohammad Javad; Bizheva, Kostadinka; Wong, Alexander

    2015-01-01

    Spectral Domain Optical Coherence Tomography (SD-OCT) is a well-known imaging modality which allows for \\textit{in-vivo} visualization of the morphology of different biological tissues at cellular level resolutions. The overall SD-OCT imaging quality in terms of axial resolution and Signal-to-Noise Ratio (SNR) degrades with imaging depth, while the lateral resolution degrades with distance from the focal plane. This image quality degradation is due both to the design of the SD-OCT imaging system and the optical properties of the imaged object. Here, we present a novel Depth Compensated SD-OCT (DC-OCT) system that integrates a Depth Compensating Digital Signal Processing (DC-DSP) module to improve the overall imaging quality via digital compensation. The designed DC-DSP module can be integrated to any SD-OCT system and is able to simultaneously compensate for the depth-dependent loss of axial and lateral resolutions, depth-varying SNR, as well as sidelobe artifact for improved imaging quality. The integrated D...

  14. Compensating laser wave-front aberration in atmosphere 1.27 km away with SBS

    Institute of Scientific and Technical Information of China (English)

    Youlun Ju(鞠有伦); Qi Wang(王骐); Deying Chen(陈德应); Xin Yu(于欣); Yuezhu Wang(王月珠)

    2003-01-01

    It is reported that the wave-front aberration produced by atmosphere disturbance can be compensated with nonlinear optics phase conjugate technology. The distance of laser propagating in atmosphere is up to 1.27 km away. The result shows that SBS phase conjugating beam energy can be focus in a little area on target. And the biggest energy of phase conjugating beam on target is up to 142 mJ.

  15. Voltage Unbalance and Harmonic Compensation in Microgrids by Cooperation of Distributed Generators and Active Power Filters

    DEFF Research Database (Denmark)

    Hashempour, Mohammad M.; Savaghebi, Mehdi; Quintero, Juan Carlos Vasquez

    2016-01-01

    , selective virtual impedance and voltage/current regulators. Based on the secondary control, at first voltage harmonic compensation and voltage unbalance compensation of point of common coupling (PCC), that might includes sensitive loads, is carried out by DGs. Voltage compensation of PCC by DGs may cause...... severe voltage distortion at DGs terminals. Thus, the coordinated control is used to mitigate the voltage distortion to the defined maximum allowable value at DGs terminals. Evaluation of the proposed hierarchical control is carried out by a simulation study....

  16. Adaptive filter design based on the LMS algorithm for delay elimination in TCR/FC compensators.

    Science.gov (United States)

    Hooshmand, Rahmat Allah; Torabian Esfahani, Mahdi

    2011-04-01

    Thyristor controlled reactor with fixed capacitor (TCR/FC) compensators have the capability of compensating reactive power and improving power quality phenomena. Delay in the response of such compensators degrades their performance. In this paper, a new method based on adaptive filters (AF) is proposed in order to eliminate delay and increase the response of the TCR compensator. The algorithm designed for the adaptive filters is performed based on the least mean square (LMS) algorithm. In this design, instead of fixed capacitors, band-pass LC filters are used. To evaluate the filter, a TCR/FC compensator was used for nonlinear and time varying loads of electric arc furnaces (EAFs). These loads caused occurrence of power quality phenomena in the supplying system, such as voltage fluctuation and flicker, odd and even harmonics and unbalancing in voltage and current. The above design was implemented in a realistic system model of a steel complex. The simulation results show that applying the proposed control in the TCR/FC compensator efficiently eliminated delay in the response and improved the performance of the compensator in the power system.

  17. Beam Dynamics in an Electron Lens with the Warp Particle-in-cell Code

    CERN Document Server

    Stancari, Giulio; Redaelli, Stefano

    2014-01-01

    Electron lenses are a mature technique for beam manipulation in colliders and storage rings. In an electron lens, a pulsed, magnetically confined electron beam with a given current-density profile interacts with the circulating beam to obtain the desired effect. Electron lenses were used in the Fermilab Tevatron collider for beam-beam compensation, for abort-gap clearing, and for halo scraping. They will be used in RHIC at BNL for head-on beam-beam compensation, and their application to the Large Hadron Collider for halo control is under development. At Fermilab, electron lenses will be implemented as lattice elements for nonlinear integrable optics. The design of electron lenses requires tools to calculate the kicks and wakefields experienced by the circulating beam. We use the Warp particle-in-cell code to study generation, transport, and evolution of the electron beam. For the first time, a fully 3-dimensional code is used for this purpose.

  18. Iron load

    Directory of Open Access Journals (Sweden)

    Filippo Cassarà

    2013-03-01

    Full Text Available Recent research addressed the main role of hepcidin in the regulation of iron metabolism. However, while this mechanism could be relevant in causing iron load in Thalassemia Intermedia and Sickle-Cell Anemia, its role in Thalassemia Major (TM is marginal. This is mainly due to the high impact of transfusional requirement into the severe increase of body iron. Moreover, the damage of iron load may be worsened by infections, as HCV hepatitis, or liver and endocrinological damage. One of the most relevant associations was found between splenectomy and increase of risk for mortality due,probably, to more severe iron load. These issues suggest as morbidity and mortality of this group of patients they do not depend only by our ability in controlling heart damage but even in preventing or treating particular infections and complications. This finding is supported by the impairment of survival curves in patients with complications different from heart damage. However, because, during recent years different direct and indirect methods to detect iron overload in patients affected by secondary hemochromatosis have been implemented, our ability to maintain under control iron load is significantly improved. Anyway, the future in iron load management remains to be able to have an iron load map of our body for targeting chelation and other medical treatment according to the single organ damage.

  19. Lidar-Assisted Feedforward Individual Pitch Control to Compensate Wind Shear and Yawed Inflow

    Science.gov (United States)

    Wortmann, Svenja; Geisler, Jens; Konigorski, Ulrich

    2016-09-01

    Lidar-assisted individual pitch control (IPC) has been investigated occasionally in recent years, focusing on the compensation of (vertical) wind shear as the main disturbance. Since yawed inflow might cause significant load fluctuations too, it is worth to compensate. Load patterns caused by yawed inflow significantly differ from those caused by wind shear, requiring a more sophisticated control algorithm. In this paper a lidar-assisted cyclic pitch feedforward control to compensate wind shear and yawed inflow is presented. The main objective is the analysis of the load patterns through a simplified aerodynamic model, which among other things focuses on a reasonable representation of the skewed wake effect. Establishing a suitable structure of the feedforward controller follows. The paper concludes with a comparison of fatigue load reductions achieved by three different controllers. Firstly, a well-known feedback individual pitch control; secondly, a feedforward controller for pure wind shear compensation and thirdly, this new feedforward controller to compensate wind shear and yawed inflow. The last two controllers use ideal lidar measurement chains.

  20. Adaptive current compensation with nonlinear disturbance observer for single-sided linear induction motor considering dynamic eddy-effect

    Institute of Scientific and Technical Information of China (English)

    DENG Jiang-ming; CHEN Te-fang; CHEN Chun-yang

    2015-01-01

    An adaptive current compensation control for a single-sided linear induction motor (SLIM) with nonlinear disturbance observer was developed. First, to maintaint-axis secondary component flux constant with consideration of the specially dynamic eddy-effect (DEE) of the SLIM, a instantaneously tracing compensation ofm-axis current component was analyzed. Second, adaptive current compensation based on Taylor-discretization algorithm was proposed. Third, an effective kind of nonlinear disturbance observer (NDOB) was employed to estimate and compensate the undesired load vibrations, then the robustness of the control system could be guaranteed. Experimental verification of the feasibility of the proposed method for an SLIM control system was performed, and it showed that the proposed adaptive compensation scheme with NDOB could significantly promote speed dynamical response and minimize speed ripple under the conditions of external load coupled vibrations and unavoidable feedback control variables measured errors, i.e., current and speed.

  1. Ongoing transients in carbonate compensation

    NARCIS (Netherlands)

    Boudreau, B.P.; Middelburg, J.J.; Hofmann, A.F.; Meysman, F.J.R.

    2010-01-01

    Uptake of anthropogenic CO2 is acidifying the oceans. Over the next 2000 years, this will modify the dissolution and preservation of sedimentary carbonate. By coupling new formulas for the positions of the calcite saturation horizon, zsat, the compensation depth, zcc, and the snowline, zsnow, to a b

  2. Compensation for oil pollution damage

    Science.gov (United States)

    Matugina, E. G.; Glyzina, T. S.; Kolbysheva, Yu V.; Klyuchnikov, A. S.; Vusovich, O. V.

    2015-11-01

    The commitment of national industries to traditional energy sources, as well as constantly growing energy demand combined with adverse environmental impact of petroleum production and transportation urge to establish and maintain an appropriate legal and administrative framework for oil pollution damage compensation. The article considers management strategies for petroleum companies that embrace not only production benefits but also environmental issues.

  3. Can Education Compensate for Society?

    Science.gov (United States)

    Pring, Richard

    2011-01-01

    The extent to which education can compensate for social disadvantage is a matter of political controversy, especially in the context of policies for social mobility. On the one hand, to blame poor achievement on social class or poverty was seen to dodge the professional responsibility of teachers. On the other, the strong correlation between…

  4. Working conditions, compensation and absenteeism.

    Science.gov (United States)

    Ose, Solveig Osborg

    2005-01-01

    This paper examines absence behaviour in relation to the working environment. A theoretical model is built in order to separate the effects of voluntary absences and absences related to ill health, where health effects are assumed to be tied to working conditions. This model is based on the Shapiro and Stiglitz efficiency wage model. In addition, work environment is introduced as a part of the compensation package. The model gives a testable hypothesis of compensating wage differentials. A panel of quarterly firm level data from 1990 to 1998 are used and the theoretical model is supported by the empirical findings. The result indicates that the workers may not be fully compensated when experiencing high levels of noise in the work area, or when the job involves a high degree of monotonous work, heavy or frequent lifting or poor work postures. Ill health, and thus increased long-term absence, is not highly related to economic variables. However, long-term absence is relatively higher if the firm is troubled with many accidents or near misses. In addition, disamenities for which workers are not fully compensated cause ill health and increased long-term absence.

  5. Stålplader gav dobbelt bæreevne (Steel plates doubled the load bearing capacity)

    DEFF Research Database (Denmark)

    Nielsen, Jan Broch

    1999-01-01

    Abstract from an examination of motor road bridge beams reinforced with steel plates on the sides and bottom. The plates doubled the load bearing capacity of the beams.......Abstract from an examination of motor road bridge beams reinforced with steel plates on the sides and bottom. The plates doubled the load bearing capacity of the beams....

  6. Heat loads and cryogenics for HE-LHC

    CERN Document Server

    Delikaris, D

    2011-01-01

    We report preliminary considerations on cryogenics for a higher-energy LHC ("HE-LHC") with about 16.5 TeV beam energy and 20-T dipole magnets. In particular we sketch the heat loads scaled on the proposed principal beam parameters and size the cryogenic plants for different operating temperature of the beam screens.

  7. 阿德福韦酯与恩替卡韦治疗低病毒载量代偿期乙肝肝硬化疗效比较%Comparison of adefovir and entecavir in treatment with low viral load hepatitis B virus related compensated cirrhosis

    Institute of Scientific and Technical Information of China (English)

    毛创杰; 王丽; 胡蓉; 曾义岚; 张琼; 康信通

    2015-01-01

    Objectives To compare the curative effect of adefovir dipivoxil ( ADV) and entecavir ( ETV) in the treatment of low viral load decompensated liver cirrhosis .Methods From 2011 Jan to 2012 June, 96 cases of low viral load decompensated liver cirrhosis caused by hepatitis B virus ( HBV-DNA 0.05);treated for 12 months, ADV group’ s HBeAg serum virological breakthrough rate was 16.7% and 2.1%, ETV group were 14.6% and 4.2%, the difference was not statistically significant ( P >0.05); treated for 12 months, 2 groups’ ALT, TB, Alb, PT were significantly improved ( P 0.05).The se-rum creatinine ( SCr) and lactic acid ( LA) more than the normal value of the upper limit were not found in both of the two groups.ADV group died of 1 case (2.1%), and there was no mortality in ETV group.Conclusion Adefovir dipivoxil or en entecavir treatment for low viral load compensated hepatitis B cirrhosis can significantly inhibited HBV -DNA replication, im-prove liver function indicators , reduce incidence of decompensated , its worthy of clinical application .%目的:比较阿德福韦酯( ADV)与恩替卡韦( ETV)治疗低病毒载量代偿期乙肝肝硬化患者的疗效。方法2011年1月—2012年6月选取低病毒载量代偿期乙肝肝硬化( HBV DNA均<2ˇ.0×104拷贝/ml )患者96例,按照随机数字表分为2组,其中48例接受阿德福韦酯抗病毒治疗( ADV组),48例接受恩替卡韦抗病毒治疗( ETV组),每1~3个月检测患者肝功能[丙氨酸氨基转移酶(ALT)、总胆红素(TB)、白蛋白(Alb)]、肾功能、甲胎蛋白、乙肝三系、血清HBV DNA、凝血酶原时间( PT)、肝脏B型超声或CT检查,随访12个月比较疗效及不良反应和病死率。结果 ADV组和ETV组12个月后血清HBV DNA 阴转率均为100%,比较差异无统计学意义( P >0.05);ADV组治疗12个月HBeAg血清转换率及病毒学突破率为16.7%、2.1%,ETV组分别为14.6%、4

  8. OPERATIONAL ACCURACY IMPROVEMENT OF DIGITAL SERVO SYSTEM CONTAINING UNBALANCED LOAD

    Directory of Open Access Journals (Sweden)

    A. Stryzhniou

    2013-01-01

    Full Text Available The paper considers a structural flowchart of a typical digital servo system and its operational principle. A method for determination of the unbalanced load effect on the accuracy of the system operation is described in the paper. The paper proposes a method for compensation of the  unbalanced load influence on the system operation. The experimental verification of the unbalanced load effect on the operational accuracy of the servo system and compensation of these influences have been executed in the paper.

  9. A Fuzzy PI Speed Controller based on Feedback Compensation Strategy for PMSM

    Directory of Open Access Journals (Sweden)

    Ou Sheng

    2015-05-01

    Full Text Available in order to solve the problem of robustness or anti-disturbance of the traditional PI speed controller in the permanent magnet synchronous motor. A fuzzy PI speed controller based on load torque feedback compensation is proposed for the permanent magnet synchronous motor. The combination of fuzzy PI control strategy and load feedback compensation method can enhance the robustness and disturbance rejection of the speed loop. According to the validated results of simulation and experiments, by using this PMSM speed controller, the robustness of the system speed control was enhanced markedly, and the capacity of anti-disturbance was also improved significantly.

  10. Design and Application of Quadrature Compensation Patterns in Bulk Silicon Micro-Gyroscopes

    Directory of Open Access Journals (Sweden)

    Yunfang Ni

    2014-10-01

    Full Text Available This paper focuses on the detailed design issues of a peculiar quadrature reduction method named system stiffness matrix diagonalization, whose key technology is the design and application of quadrature compensation patterns. For bulk silicon micro-gyroscopes, a complete design and application case was presented. The compensation principle was described first. In the mechanical design, four types of basic structure units were presented to obtain the basic compensation function. A novel layout design was proposed to eliminate the additional disturbing static forces and torques. Parameter optimization was carried out to maximize the available compensation capability in a limited layout area. Two types of voltage loading methods were presented. Their influences on the sense mode dynamics were analyzed. The proposed design was applied on a dual-mass silicon micro-gyroscope developed in our laboratory. The theoretical compensation capability of a quadrature equivalent angular rate no more than 412 °/s was designed. In experiments, an actual quadrature equivalent angular rate of 357 °/s was compensated successfully. The actual compensation voltages were a little larger than the theoretical ones. The correctness of the design and the theoretical analyses was verified. They can be commonly used in planar linear vibratory silicon micro-gyroscopes for quadrature compensation purpose.

  11. Design, development and fabrication of a deployable/retractable truss beam model for large space structures application

    Science.gov (United States)

    Adams, Louis R.

    1987-01-01

    The design requirements for a truss beam model are reviewed. The concept behind the beam is described. Pertinent analysis and studies concerning beam definition, deployment loading, joint compliance, etc. are given. Design, fabrication and assembly procedures are discussed.

  12. Nonlinear Compensation of Solar Array Simulators with Dual Power Regulation

    Science.gov (United States)

    Mizrah, E. A.; Tkachev, S. B.; Poymanov, D. N.; Fedchenko, A. S.

    2016-11-01

    During the tests of the spacecraft electrical systems there is a need for simulators of individual parts of the spacecrafts, in particular, solar array simulators (SAS). One of the topologies of medium and high power SAS simulators has dual control of consumed power and contains series or parallel connected linear and switching regulators. This topology allows to provide wide bandwidth and high efficiency, but the range of the resistance change of periodically switched SAS load is limited to the value of the stabilized attribute. Nonlinear compensator (NC) allows to reduce the average feedback voltage of the switching regulator in case of periodic load switching, which, in turn, allows to increase the average value of the stabilized attribute. The describing function method provides a mathematical description of the NC electrical circuit, which allows to select parameters of NC that eliminate the excitation of self-oscillation based on the SAS load switching frequency range and to study the switching regulator stability.

  13. Bending and rotational behaviour of semi-continuous composite beams

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Stresses and deflections were measured in various semi-continuous composite beams.The bending and rotational capacities of the composite connections were measured in terms of beam curvatures and deflections by using two full-scale semi-rigid composite frames with monotonic loadings.The effect of semi-rigid connections on the performance of composite beams with various loadings was compared with predictions and codes.The tests show that the semi-continuous composite beams are more economic and effective than the simple or continuous composite beams.The semi-rigid connections affect the bending capacities and beam deflections,so the connection behavior should be considered in the design of composite beams.Yielding analysis of the steel beam bottom flange has some influence on the deflection calculation of composite beams.

  14. 基于能量变分剪切效应空间梁单元刚度矩阵及荷载列阵推导%DERIVATION OF ELEMENT STIFFNESS MATRIX AND LOAD ARRAY FOR SPACE BEAM WITH SHEAR EFFECT BASED ON ENERGY VARIATION

    Institute of Scientific and Technical Information of China (English)

    潘文军; 叶献国

    2012-01-01

    为了系统研究空间梁单元考虑剪切变形影响时的刚度矩阵及荷载列阵,将能量变分原理应用于空间梁的单元分析。建立了考虑剪切效应的空间梁单元位移函数,利用最小势能原理导出了这种空间梁单元的刚度矩阵和荷载列阵的表达式,显式积分得到单元刚度矩阵,同时计算了平面内部分非节点荷载作用下的等效节点荷载,修正了相关文献中的部分错误。计算结果表明:该方法所得到的单元刚度矩阵与相关文献中其他方法的计算结果完全一致,为编制空间巨型结构的有限元程序奠定基础,对推算其他类型单元刚度矩阵及其荷载列阵也具有理论意义和应用价值。%In order to study systematically the stiffness matrix and load array of space beam element with the impact of shear deformation, the element was analyzed by the energy variation principle. The displacement functions for space beam element with shear deformation effect were put forward, and then expressions of element stiffness matrix and load array for this beam were deduced strictly by the minimum potential energy principle. Explicit integration was carried out for the element stiffness matrix and the equivalent nodal loads under some forms of no-node load within a plane were calculated as well, which had revised the mistakes in relevant reference. Results show that the element stiffness matrix computed by the method is consistent with those in related documents calculated by other methods, which makes a foundation for compiling the finite element procedure for space mega frame structure. Which has a good theoretical and practical value in the calculation of the element stiffness matrixes and load arrays for other elements as well.

  15. Beam collimator

    CERN Multimedia

    1977-01-01

    A four-block collimator installed on a control table for positioning the alignment reference marks. Designed for use with SPS secondary beams, the collimator operates under vacuum conditions. See Annual Report 1976 p. 121 and photo 7701014.

  16. Finger-jointed beams in bending

    DEFF Research Database (Denmark)

    Andreasen, Lotte; Hoffmeyer, Preben

    1997-01-01

    An investigation of the dynamic and static fatique of finger-jointed beams in bending was carried out. Results were obtained for five different frequencies from static loading to a load cycle period of two minutes. A total of seven series were long-term tested and five series were short-term tested...

  17. Analytical determination of the ultimate strength of sandwich beams

    Science.gov (United States)

    Theotokoglou, Efstathios E.

    1996-09-01

    An analytical determination of the ultimate strength of a typical GRP/PVC sandwich beam has been performed. These beams represent common building practise in marine applications. Equations describing the behaviour of a sandwich panel under beam loading and various failure modes have been developed. The method has been applied to predict the ultimate load for a simple supported sandwich beam. The critical loads have been compared with those from the experimental investigation of a typical bulkhead-to-hull GRP/PVC sandwich T-joint under pull out forces.

  18. Measurements of fluctuating gas temperatures using compensated fine wire thermocouples

    Science.gov (United States)

    Nina, M. N. R.; Pita, G. P.

    1985-09-01

    Thermocouples with three different wire diameters (15, 40 and 50 microns) were used in association with an analog compensation circuit connected to a data acquisition system. Measurements of the time constant were performed using two different heating techniques; Joule effect and external heating by laser beam. The thermocouples were used to quantify the fluctuating temperature field in a hot air jet and in a premixed propane flame. In the reacting case the catalytic effect was evaluated by comparing coated and uncoated wires. Conclusions were also obtained regarding frequency spectra, temperature probability distribution function and time constant.

  19. Simulating Transient Effects of Pulsed Beams on Beam Intercepting Devices

    CERN Document Server

    Richter, Herta; Noah Messomo, Etam

    2011-01-01

    The development in the physics community towards higher beam power through the possibilities of particle accelerators lead to challenges for the developers of elements which are exposed to effect of particle beams (beam intercepting devices = BIDs). For the design of BIDs, the increasing heat load onto these devices due to energetic and focused beams and - in most cases - their highly pulsed nature has to be taken into account. The physics requirements are sometimes opposed to the current state of the art. As one possibility of many in combining the different aspects for these ambitious demands, two highly developed computer programs, namely FLUKA and ANSYS AUTODYN, were joined for this dissertation. The former is a widely enhanced Monte-Carlo-code which specializes on the interaction of particles with static matter, while the latter is a versatile explicit code for the simulation of highly dynamic processes. Both computer programs were developed intensively over years and are still continuously enhanced in o...

  20. Ældre betonbroers bæreevne (Load bearing capacity of old concrete bridges)

    DEFF Research Database (Denmark)

    Nielsen, Anders

    1999-01-01

    was carried. - The other is a motor way bridge from 1939, which were reinforced 1991 with external steel plates on the areas of shear on the beams. Four beams were carried to our laboratory and load tested. The steel plates have doubled the load bearing capacity of the beams....

  1. Investigation of innovative steel runway beam in industrial building

    Indian Academy of Sciences (India)

    Mahyar Maali; Abdulkadir Cüneyt Aydin; Merve Sağiroğlu

    2015-10-01

    The design of a runway beam for overhead cranes is of great importance when constructing steel structures, as is the lateral-torsional buckling (LTB) value obtained for I-beam sections. Therefore, engineers must always consider the optimal design of these beams under overhead cranes loads. In this study, runway beams of three overhead crane groups were analyzed for LTB, and a sinusoidal runway beam body was developed. These runway beams with different sinusoidal angles were analyzed by using the finite element method (ABAQUS) and compared to each other and other runway IPE-IPN beam sections; furthermore, all models were compared with the Canadian Institute of Steel Construction standard. As a result, a new method was proposed for developing sinusoidal runway beams for overhead cranes. The sinusoidal runway beam has lower weight than runway IPE-IPN beam sections. Ultimately, a sinusoidal beam body was developed practically with a scale of 1:1.

  2. Intralimb compensation strategy depends on the nature of joint perturbation in human hopping.

    Science.gov (United States)

    Chang, Young-Hui; Roiz, Ronald A; Auyang, Arick G

    2008-01-01

    Due to the well-described spring-mass dynamics of bouncing gaits, human hopping is a tractable model for elucidating basic neuromuscular compensation principles. We tested whether subjects would employ a multi-joint or single-joint response to stabilize leg stiffness while wearing a spring-loaded ankle-foot orthosis (AFO) that applied localized resistive and assistive torques to the ankle. We analyzed kinematics and kinetics data from nine subjects hopping in place on one leg, at three frequencies (2.2, 2.4, and 2.8Hz) and three orthosis conditions (freely articulating AFO, AFO with plantarflexion resistance, and AFO with plantarflexion assistance). Leg stiffness was invariant across AFO conditions, however, compensation strategy depended upon the nature of the applied load. Biological ankle stiffness increased in response to a resistive load at twice the rate that it decreased with an assitive load. Ankle adjustments alone fully compensated for an assistive load with no net change in combined (biological plus applied) total ankle stiffness (p > or =0.133). In contrast, a resistive load resulted in a 7.4-9.0% increase in total ankle stiffness across frequencies and a concomitant 10-15% increase in knee joint stiffness at each frequency (pcompensation strategies that are specific to the nature of the joint loading.

  3. 16 CFR 16.16 - Compensation.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Compensation. 16.16 Section 16.16 Commercial... MANAGEMENT § 16.16 Compensation. (a) Committee members. Unless otherwise provided by law, the Commission... cost to the Commission. The compensation to be paid to such consultant may not exceed the maximum...

  4. 75 FR 76079 - Sound Incentive Compensation Guidance

    Science.gov (United States)

    2010-12-07

    ... Office of Thrift Supervision Sound Incentive Compensation Guidance AGENCY: Office of Thrift Supervision... collection. Title of Proposal: Sound Incentive Compensation Guidance. OMB Number: 1550-0129. Form Number: N/A... compensation arrangements at a financial institution do not encourage employees to take excessive risks....

  5. 45 CFR 1604.5 - Compensation.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Compensation. 1604.5 Section 1604.5 Public Welfare... Compensation. (a) Except as provided in paragraph (b) of this section and § 1604.7(a), a recipient's written policies shall not permit a full-time attorney to receive any compensation for the outside practice of...

  6. 34 CFR 106.54 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Compensation. 106.54 Section 106.54 Education... Compensation. A recipient shall not make or enforce any policy or practice which, on the basis of sex: (a) Makes distinctions in rates of pay or other compensation; (b) Results in the payment of wages...

  7. 6 CFR 17.515 - Compensation.

    Science.gov (United States)

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Compensation. 17.515 Section 17.515 Domestic... in Employment in Education Programs or Activities Prohibited § 17.515 Compensation. A recipient shall... of pay or other compensation; (b) Results in the payment of wages to employees of one sex at a...

  8. 22 CFR 146.515 - Compensation.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Compensation. 146.515 Section 146.515 Foreign... Education Programs or Activities Prohibited § 146.515 Compensation. A recipient shall not make or enforce... compensation; (b) Results in the payment of wages to employees of one sex at a rate less than that paid...

  9. 32 CFR 196.515 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 2 2010-07-01 2010-07-01 false Compensation. 196.515 Section 196.515 National... Compensation. A recipient shall not make or enforce any policy or practice that, on the basis of sex: (a) Makes distinctions in rates of pay or other compensation; (b) Results in the payment of wages to employees of one...

  10. 41 CFR 101-4.515 - Compensation.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Compensation. 101-4.515... Employment in Education Programs or Activities Prohibited § 101-4.515 Compensation. A recipient shall not... pay or other compensation; (b) Results in the payment of wages to employees of one sex at a rate...

  11. 45 CFR 618.515 - Compensation.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Compensation. 618.515 Section 618.515 Public... Compensation. A recipient shall not make or enforce any policy or practice that, on the basis of sex: (a) Makes distinctions in rates of pay or other compensation; (b) Results in the payment of wages to employees of one...

  12. 24 CFR 3.515 - Compensation.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Compensation. 3.515 Section 3.515... Compensation. A recipient shall not make or enforce any policy or practice that, on the basis of sex: (a) Makes distinctions in rates of pay or other compensation; (b) Results in the payment of wages to employees of one...

  13. 10 CFR 5.515 - Compensation.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Compensation. 5.515 Section 5.515 Energy NUCLEAR... Activities Prohibited § 5.515 Compensation. A recipient shall not make or enforce any policy or practice that, on the basis of sex: (a) Makes distinctions in rates of pay or other compensation; (b) Results in...

  14. 45 CFR 86.54 - Compensation.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Compensation. 86.54 Section 86.54 Public Welfare... in Employment in Education Programs or Activities Prohibited § 86.54 Compensation. A recipient shall... of pay or other compensation; (b) Results in the payment of wages to employees of one sex at a...

  15. 7 CFR 15a.54 - Compensation.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Compensation. 15a.54 Section 15a.54 Agriculture Office... Activities Prohibited § 15a.54 Compensation. A recipient shall not make or enforce any policy or practice which, on the basis of sex: (a) Makes distinctions in rates of pay or other compensation; (b) Results...

  16. 13 CFR 113.515 - Compensation.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Compensation. 113.515 Section 113... Compensation. A recipient shall not make or enforce any policy or practice that, on the basis of sex: (a) Makes distinctions in rates of pay or other compensation; (b) Results in the payment of wages to employees of one...

  17. 22 CFR 229.515 - Compensation.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Compensation. 229.515 Section 229.515 Foreign... in Education Programs or Activities Prohibited § 229.515 Compensation. A recipient shall not make or... compensation; (b) Results in the payment of wages to employees of one sex at a rate less than that paid...

  18. 18 CFR 1317.515 - Compensation.

    Science.gov (United States)

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Compensation. 1317.515... Compensation. A recipient shall not make or enforce any policy or practice that, on the basis of sex: (a) Makes distinctions in rates of pay or other compensation; (b) Results in the payment of wages to employees of one...

  19. 47 CFR 51.221 - Reciprocal compensation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Reciprocal compensation. 51.221 Section 51.221... Obligations of All Local Exchange Carriers § 51.221 Reciprocal compensation. The rules governing reciprocal compensation are set forth in subpart H of this part....

  20. 45 CFR 2555.515 - Compensation.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 4 2010-10-01 2010-10-01 false Compensation. 2555.515 Section 2555.515 Public... Compensation. A recipient shall not make or enforce any policy or practice that, on the basis of sex: (a) Makes distinctions in rates of pay or other compensation; (b) Results in the payment of wages to employees of one...