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Industry Applications, IEEE Transactions on

Issue 4 • Date Jul/Aug 2000

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Displaying Results 1 - 25 of 33
  • Impact of cross saturation in synchronous reluctance motors of the transverse-laminated type

    Page(s): 1039 - 1046
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    The cross-saturation phenomenon in synchronous reluctance motors is extensively analyzed, with a main reference to motors of the transverse-laminated type. A mixed theoretical and experimental approach is adopted, aiming at definition of the motor's behavior when large overload currents are driven up to ten times the rated current. As a consequence, a special test and measuring procedure has been adopted. The obtained results are used to check the validity of the adopted model and to prove the unexpected overload performance of this motor View full abstract»

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  • Permanent-magnet machines with powdered iron cores and prepressed windings

    Page(s): 1077 - 1084
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    This paper presents a permanent-magnet servomotor, built with a powdered iron stator, which has been designed to take full advantage of the properties of the material. There are a number of important design features which are not possible with laminated cores. For example, the core back is axially extended over the end windings, the armature core components are subdivided and preformed stator coils are used. The coils are prepressed to form a solid component with an exceptionally high fill factor (78%). The prototype offers far superior performance to a conventionally laminated commercial machine, manufactured in the same frame View full abstract»

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  • Thermal effects of stray load losses in induction machines

    Page(s): 1085 - 1093
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    Additional heat produced in induction machines due to stray load losses could influence the plant rating, winding insulation design, operating limit and the machine protection design. Quantifying this additional heat and stray load losses accurately and, hence, investigating the extent of some of these influences are the concerns of this paper. Two experimentally verified models, electrical and thermal, are presented. Results of a practical exercise on the measurement of stray load losses by different test methods are reported. The study, thereafter, gives insight into the relationship between stray load losses and the influences mentioned above and contribute results, which are useful to the design and operation of this machine and its protection View full abstract»

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  • Soft-switched three-level capacitor clamping inverter with clamping voltage stabilization

    Page(s): 1165 - 1173
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    This paper proposes a zero-voltage-switching scheme for the three-level capacitor clamping inverter. The proposed small-rating auxiliary circuit ensures not only zero-voltage switching of the main switches and zero-current switching of the auxiliary switches, but the clamping capacitor voltage of the inverter is also stabilized. The scheme prevents any voltage or current spikes from happening over the main or auxiliary switches and no modulation constraints are incurred. Operation, analysis, designing, and testing aspects of the scheme are detailed View full abstract»

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  • Electrostatic application of pollen sprays: effects of charging field intensity and aerodynamic shear upon deposition and germinability

    Page(s): 998 - 1009
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    Pollination deficiencies limit the biological production efficiency of certain high-value agricultural crops. To enhance pollination, an aerodynamic-electrostatic spray process has been developed which incorporates electric forces to transfer ~60-μm pollen grains to receptive stigmatic surfaces of flowers. Osmotically balanced carrier-liquid suspensions of almond pollen, pneumatically atomized at up to 276 kPa and induction charged to 12 mC/kg in 1.6-MV/m applied fields, are shown to maintain at least 80% germinability upon electrostatic deposition. Compared with uncharged spray, charged pollen deposition was significantly (∝=0.01) increased 5.6-fold as averaged across various target orientations. For difficult targets parallel to the spray's air-carrier stream, the electrodeposition benefit for pollen was maximum (12-fold increase) and air-pressure effects were most pronounced View full abstract»

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  • High-frequency class-D converter driving with feedback capacitors for electrodeless fluorescent lamps

    Page(s): 1033 - 1038
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    This paper presents a novel class-D converter for electrodeless fluorescent lamps (EFLs) in the several megahertz frequency. The proposed converter is a self-oscillating type and it uses the feedback capacitors to supply the gate voltages to the switching devices of a half-bridge inverter via gate circuits. The converter is suitable not only for a conventional EFL but also a choke-coil-less type which uses an exciting coil instead of a choke coil. The oscillating frequency is changed depending on DC voltages, especially in the choke-coil-less type. In this case, the gate circuits compensates both the off interval of the switching devices and a phase angle in order to stabilize the power factor. A prototype EFL with and without the choke coil operated steadily on the frequency of 2.5 MHz, and the temperature of the MOSFET could be kept below 55°C for both cases View full abstract»

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  • Design refinement of synchronous reluctance motors through finite-element analysis

    Page(s): 1094 - 1102
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (292 KB)  

    In this paper, the key points in the design of synchronous reluctance motors are first evidenced and discussed, that is, the choice of rotor type, the stator-rotor joint design, and the optimization of the rotor structure. A purposely designed finite-element code is then introduced and validated, on the basis of properly obtained experimental data. Measured and computed torques are compared, with emphasis on the evaluation of the torque ripple. Last, the finite-element method code is used to illustrate some aspects of the stator-rotor design and to show the torque-ripple performance of different types of machine structure View full abstract»

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  • A novel compact PMSM with magnetic bearing for artificial heart application

    Page(s): 1061 - 1068
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (612 KB)  

    This paper describes a novel compact permanent-magnet synchronous motor with a configuration of axial-field slotted windings. It is designed for driving an artificial heart. Both the motor rotor and the pump impeller of the artificial heart are levitated by a magnetic bearing. Structure description, design considerations, and analyses for the motor and bearing are presented in this paper View full abstract»

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  • DSP-based tension control and data acquisition for paper machine rewind roll drive

    Page(s): 1018 - 1025
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    A digital-signal-processor-based control technique with constant tension control for the rewind roll of a paper machine is presented in this paper. The proposed methodology makes use of a digital signal processing technique to investigate the stability of a multiple closed-loop control system and then partition its operating area into optimal working regions. A novel data acquisition method is introduced in this paper to obtain fast responses of speed and tension. This technique is characterized by high reliability and flexibility in industrial applications View full abstract»

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  • Laminated steel eddy-current loss versus frequency computed using finite elements

    Page(s): 1132 - 1137
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    Eddy-current loss in laminated steel cores is computed with unusual planar eddy finite elements over the wide frequency range produced in AC motor drives. The loss computed by the finite element method at low frequencies is shown to agree within 1% with a common simple formula. A formula used by radio-frequency engineers is shown to agree within 1% with the finite-element results at very high frequencies. The loss calculations are also compared with published curves from a steel manufacturer. At medium frequencies, no simple formula exists and, thus, the core loss computed by finite elements should be useful in the design of chokes and motors of AC variable-frequency drives View full abstract»

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  • Performance of an SCR-inverter-based commutatorless series motor with load commutation and unaided startup capability

    Page(s): 1151 - 1157
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    This paper examines the starting and variable-speed performance of a silicon-controlled-rectifier-based commutatorless series motor with special emphasis on the commutating process for the operation of a self-controlled synchronous machine in the load-commutated mode, unassisted by extra components or special techniques, even at very low speeds, including starting. A dynamic simulation of the drive, in which the field winding of the synchronous machine is located in the DC link has been presented, the results of which are validated by comparison with those of an experimental prototype. The influence of the damper windings on the commutation process and in the suppression of the voltage spikes so generated, and in reducing overlap times, has also been studied. A phasor-diagram-based steady-state analysis predicts the parameters of suitable machines for such an operation. The inherent series characteristics of this drive, its high power factor, and self-starting capability will find applications in large-power traction drives, flywheel energy storage systems, centrifugal pumps, etc View full abstract»

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  • Toward fulfilling the robotic farming vision: advances in sensors and controllers for agricultural applications

    Page(s): 1026 - 1032
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (108 KB)  

    Real-time control is becoming an integral part of modern machine systems for high-quality agricultural production. Maintaining consistently high-quality agricultural production while keeping up with growing labor shortages is a challenge. Providing a workplace for labourers which meets increasingly rigorous safety requirements and environmental constraints is likewise a challenge. More appropriate energy management and soil management have also motivated real-time control applications. Appropriate sensing and control systems can reduce labor requirements, function in difficult environments, and allow vehicles to adapt to varying soil chemical and physical states. Labor shortages and environmental constraints coupled with the reality of spatial variability of chemical and physical properties among and within agricultural production areas readily explain the migration toward real-time control of agricultural equipment. This paper presents a review of the most recent advances in the development of sensors and controllers for agricultural applications View full abstract»

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  • Salient-rotor PM synchronous motors for an extended flux-weakening operation range

    Page(s): 1118 - 1125
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB)  

    This paper proposes some novel designs of permanent-magnet synchronous motors for extending their flux-weakening capabilities. According to such a proposal, the motors are characterized by a saliency ratio ld/lq greater than one, whereas classical designs exhibit a saliency ratio lower than one. The innovative and classical design solutions are deeply compared in the paper. In order to understand better the basic differences in the motor design, the same base and flux-weakening performance are fixed. The influence of the saliency ratio on inverter voltampere ratings, maximum feasible speed, and current control characteristics is highlighted and discussed View full abstract»

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  • Prediction of starting performance of PM motors by DC decay testing method

    Page(s): 1053 - 1060
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB)  

    This paper presents a method to predict the direct- and quadrature-axes operational impedances and starting performance of permanent-magnet (PM) motors by a simple standstill response testing method using a small-capacity DC power supply unit. In this method, not only the starting performance but also the direct- and quadrature-axes synchronous machine constants (synchronous, transient, and subtransient reactances) and equivalent circuit constants are calculated. This proposed strategy, tentatively named the DC decay testing method, is carried out on a 3.7-kW 200-V 22. A 100-Hz four-pole interior PM motor with a damper winding. The results measured by on-load tests and those predicted by the proposed method on starting performance demonstrate the validity and usefulness of the proposed method View full abstract»

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  • The brushless doubly fed reluctance machine and the synchronous reluctance machine-a comparison

    Page(s): 1103 - 1110
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    The brushless doubly fed reluctance machine (BDFRM) is related to the better known brushless doubly fed induction machine (BDFIM). Research into doubly fed machines is motivated by the fact that they allow the use of a partially rated inverter in many variable-speed applications. Research into the BDFRM has been largely ignored in comparison to the BDFIM, despite the fact that it has the potential for greater efficiency as compared to the BDFIM, and the rotor is simpler to manufacture. This paper compares the BDFRM and its singly fed cousin, the synchronous reluctance machine. This is a natural comparison since both machines use the same reluctance rotor. The first part of the paper establishes relationships between the inductances of the two machines. This is then used to facilitate a comparison using the constraints that both machines have the same amount of active material, i.e., the same amount of copper and iron, and that the copper losses for both machines are the same. This analysis also allows an approximate comparison with the conventional squirrel-cage induction machine. The analysis is carried out using machine-independent normalizations View full abstract»

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  • A robust digital current control method for active power filters

    Page(s): 1158 - 1164
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB)  

    A robust digital current control strategy for active power filters using voltage-source converters is presented. The proposed control system is designed and implemented in the form of an internal model control structure and takes the presence of computational time-delay into account. As a result, it provides an effectively overshoot-free reference-to-output response. The stability of the closed-loop system has much lower sensitivity with respect to parameter uncertainties compared to the case when a conventional predictive controller is used. The experimental results obtained from a digital-signal-processor-based single-phase experimental active power filter are also reported View full abstract»

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  • Coaxial current transformer for test and characterization of high-power semiconductor devices under hard and soft switching

    Page(s): 1181 - 1188
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    The use of a coaxial current transformer (CCT) is an interesting choice for pulsed measurement of current through power devices during switching transients. The CCT is used to reflect current for convenient external measurement with minimal insertion impedance in the critical power circuit. This paper analyzes the characteristics of the CCT and explains how it can be integrated into test setups for both press-pack and module packages. Finite-element techniques are applied to the study of the CCT to obtain detailed electrical and magnetic characteristics. Current distribution in the primary and secondary circuits, flux densities, and insertion inductance and resistance are among the design information that can be obtained through finite-element analysis. Analytical and numerical results are obtained for the proposed CCT that is integrated in test setups for MOS turn-off thyristors (press-pack) and high-voltage insulated gate bipolar transistors (module) characterization View full abstract»

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  • Challenges of supplying electric power to a large industrial customer in rural areas

    Page(s): 972 - 977
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (104 KB)  

    As the economy in rural areas changes, many local leaders are attracting new large industrial clients into the area. When a large industrial business does locate in a service area, the rural electric cooperative is faced with many issues: the impact of the new load on existing system infrastructures; the potential issue of power quality on its system; and its impact on its customers. This requires that, before a large industrial customer is added, careful studies are made regarding rates, interconnection guidelines, and protection issues. The new customer may require state-of-the-art relay devices and fast-track-type installations to meet startup demands. The complexity of the new systems and fast-track construction may require the cooperative to augment its staff with added expertise. This paper discusses these challenges of supplying electric power to a large industrial customer in rural areas View full abstract»

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  • Molecular surgery of DNA based on electrostatic micromanipulation

    Page(s): 1010 - 1017
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    A novel method for the space-resolved dissection (molecular surgery) of deoxyribonucleic acid (DNA) using electrostatic molecular manipulation is proposed and demonstrated. In conventional biochemistry, DNA-cutting enzymes and DNA are mixed in water, so the cutting reactions occur only by stochastic chances. In contrast, the present method is based upon a physical manipulation and enables the reproducible cutting of DNA at any desired position along the DNA molecule. In order to realize this space-resolved cutting, the target DNA is stretched straight by electrostatic orientation and anchored on a solid surface by dielectrophoresis, using the high-intensity (1 MV/m) high-frequency (1 MHz) field created in microfabricated electrodes. It is found that, for the enzymatic cutting to occur, the DNA strand must be immobilized in such a way as to allow the enzyme to bind and interact with DNA. For this purpose, an electrode system is developed, in which DNA is anchored to the substrate only at the ends of the molecule, leaving the middle free. The enzyme, on the other hand, is immobilized on a latex particle having 1-μm diameter, and optical tweezers are used to hold it and press it against the stretched and immobilized DNA. The enzymes used are: (1) DNaseI (cuts DNA regardless of the base sequence) and (2) HindIII (a restriction enzyme; cuts DNA at a specific sequence). It is demonstrated that, when a DNaseI-labeled bead is brought into contact with the immobilized DNA, DNA is cut instantaneously. On the other hand, when the restriction enzyme is used, the bead must be moved along the strand for a certain distance until it is finally cut. The authors' interpretation for this enzyme dependence is that the restriction enzyme has to get into the grooves of DNA to find the restriction sites, so the condition for the molecular contour fitting of the DNA and the enzyme are stricter compared with the case of the simple backbone-cutting enzyme DNaseI. The technique presented in this paper is expected to realize space-resolved molecular surgical operations, not just limited to dissections, but also for chemical modifications, or even insertion of genes View full abstract»

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  • Large-band reduction of magnetic vibrations of induction machines with “breaking-of-impedance” interface

    Page(s): 1126 - 1131
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (408 KB)  

    Magnetic vibration of induction machines is reduced, on a large-frequency band, with a breaking-of-impedance interface between stator core and frame. This device is designed with strong tangential stiffness and low radial stiffness. Two-dimensional finite-element (FE) dynamic response is proposed. It is based firstly on experimental determination of magnetic forces with search coils on a half polar pitch on the stator bore. Secondly, all characteristics of windings are determined versus temperature and frequency and homogenized with a linear mixing law. Thirdly, a FE modal analysis is optimized on the target function based on experimental natural frequencies, in order to identify the equivalent mechanical parameters of wound slots View full abstract»

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  • Mathematical modeling of powder paint particle trajectories in electrostatic painting

    Page(s): 992 - 997
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (140 KB)  

    The trajectories of charged powder particles in an electrostatic powder coating system were modeled considering electrical and fluid forces. The mathematical model employed an iterative technique wherein the charge simulation method was used to compute the electric field strength and the method of characteristics was used to compute the charge density in the gun-to-target region. The fluid flow between the electrostatic gun and the target was modeled using interpolated experimental data assuming stagnation point flow. Particle trajectories were simulated for size range 10-40 μm and charge-to-mass ratios of -0.1 to -1 μC/g. The simulation results showed good agreement with experimental data (charge and mass measurements) at several collection points on the painting target and provided valuable information concerning particle deposition View full abstract»

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  • Two-dimensional finite-element analysis of a high-force-density linear switched reluctance machine including three-dimensional effects

    Page(s): 1047 - 1052
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (588 KB)  

    This paper presents results of a finite-element analysis (FEA) study on a high-force-density linear switched reluctance motor. Analytical study by means of an electric circuit analog of the same motor was presented in a previous paper. For this refined analysis, two-dimensional (2-D) FEA is used along with a novel way of accounting for three-dimensional (3-D) effects. It is shown that, with minimal 3-D FE modeling, the 2-D FE model can be used to satisfactorily include the third-dimensional effects due to end turns and short stack length relative to the motor axial length. FEA results are presented and compared with measured results. Comparison with measured forces shows the effectiveness of the model View full abstract»

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  • A power-line conditioner based on flying-capacitor multilevel voltage-source converter with phase-shift SPWM

    Page(s): 965 - 971
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    In this paper, a new power-line conditioning system is proposed. This system is constructed by a flying-capacitor multilevel voltage-source converter (VSC) and two reactors. The phase-shift sinusoidal pulsewidth modulation switching scheme is applied to control the switching devices of this converter. Due to this multilevel VSC and the switching scheme applied to this converter, the system is applicable to distribution systems or industrial applications. The reactive power compensation, harmonic suppression and load-balancing functions of the power-line conditioner are analyzed. A novel and effective startup procedure is proposed to start up the system. System simulation is carried out to verify the theoretical analysis results View full abstract»

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  • Locked-rotor and acceleration testing of large induction machines-methods, problems, and interpretation of the results

    Page(s): 958 - 964
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    The measurement of locked-rotor current, torque, and power factor has been a standard test for induction machines for many years. Measurement of torque has evolved from using a brake, a dynamometer, a torque arm, and scale, through strain gauges and load cells to acceleration tests. The test must be of short duration to prevent damage to the machine and large machines present problems because of facility limitations in either kilovoltampere or torque measurement. A single test at reduced voltage when prorated to operating voltage by the square of the ratio of rated voltage to test voltage neglects the impact of saturation and results in significantly lower values of predicted torque and current. This paper discusses several methods for performing the locked-rotor and the speed-torque tests on large machines. It also discusses some of the problems associated with the test methods and shows how the tests can be performed and the results evaluated to account for saturation effects. Finally, the paper shows how to extract some machine circuit parameters from the test data View full abstract»

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  • Asynchronous motor protection against dynamic instabilities

    Page(s): 978 - 985
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    This paper deals with the dynamic behavior of the electric power system of a Venezuelan oil refinery (El Palito Refinery, Puerto Cabello, Venezuela), which includes a 6000-hp asynchronous motor working as a motor or generator (M/G) coupled to the power recovery unit (PRU) shaft at the fluidized catalytic cracking plant (FCC). Problems associated with inappropriate maintenance at the external power utility, whose system is linked with the national interconnected grid, have decreased the electric power system reliability at the refinery. Critical failure events, up to third-order contingency events, have been occurring at the refinery frequently over the past few years. Once these kind of events take place, the 6000-hp motor tends to balance the system generating or consuming electric power, but due to the large equivalent inertia in the external utility, the 6000-hp motor trips before the refinery normal operating conditions have been restored. Then, both the FCC and PRU shut down, the FCC Plant being a vital process unit within an oil refinery. This paper involves a dynamic study of those critical failure events in order to properly set protective relaying schemes and, thus, ensure a safe and reliable operation of the refinery electric power system, while establishing dynamic stability limits for the M/G View full abstract»

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Aims & Scope

The scope of the IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS includes all scope items of the IEEE Industry Applications Society, that is, the advancement of the theory and practice of electrical and electronic engineering in the development, design, manufacture, and application of electrical systems, apparatus, devices, and controls to the processes and equipment of industry and commerce; the promotion of safe, reliable, and economic installations; industry leadership in energy conservation and environmental, health, and safety issues; the creation of voluntary engineering standards and recommended practices; and the professional development of its membership.

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