• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2178-2186
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• 2018

Online identification of load parameters is the premise of establishing a stable and highly-efficient ICPT (Inductive Coupled Power Transfer) system. However, compared with pure resistive load, precise identification of composite load, such as resistor-inductance load and resistance-capacitance load, is more difficult. This paper proposes a method for detecting the composite load parameters of ICPT system utilizing harmonics. In this system, the fundamental and harmonic wave channel are connected to the high frequency inverter jointly. The load parameter values can be obtained by setting the load equation based on the induced voltage of secondary-side network, the fundamental wave current, as well as the third harmonic current effective value received by the secondary-side current via Fourier decomposition. This method can achieve precise identification of all kinds of load types without interfering the normal energy transmission and it can not only increase the output power, but also obtain higher efficiency compared with the fundamental wave channel alone. The experimental results with the full-bridge LCCL-S type voltage-fed ICPT system have shown that this method is accurate and reliable.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.11
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• pp.1837-1843
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• 1997

This study experimentally demonstrates the use of active muffler attached to the automotive exhaust system to reduce exhaust noise. For improving the signal to noise ratio in the process of estimation of secondary path transfer functions, the on-line algorithm that conventional inverse modeling is combined with adaptive line enhancer is used as the control algorithm. Active muffler is designed that the primary noise and the control sound are propagated as a plane wave in the outlet. Therefore, the error microphone could be placed out of the tail pipe center of a high temperature and the radiation noise to the outside could be reduced in the whole area around the outlet. The control experiment for reducing exhaust noise with active muffler is implemented during run-up at no load. From the experimental results presented, compared with the conventional off-line method, the proposed on-line method is capable to acquire a reduction of exhaust noise above 5 dB in overall sound power level.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4361-4365
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• 2011

The nucleophilic substitution reactions of bis(N,N-dimethylamino) phosphinic chloride (3) with substituted anilines ($XC_6H_4NH_2$) and deuterated anilines ($XC_6H_4ND_2$) are investigated kinetically in acetonitrile at $65.0^{\circ}C$. The anilinolysis rate of 3 is rather slow to be rationalized by the conventional stereoelectronic effects. The magnitudes of ${\rho}_X$ (= -6.42) and ${\beta}_X$ (= 2.27) values are exceptionally great. The deuterium kinetic isotope effects (DKIEs; $k_H/k_D$) are secondary inverse ($k_H/k_D$ = 0.69-0.96). A concerted $S_N2$ mechanism involving a backside attack is proposed on the basis of secondary inverse DKIEs and the variation trend of the $k_H/k_D$ values with X. The anilinolyses of six phosphinic chlorides in MeCN are briefly reviewed by means of DKIEs, steric effects of the two ligands, positive charge of the reaction center phosphorus atom, and selectivity parameters to obtain systematic information on phosphoryl transfer reaction mechanism.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.155-165
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• 1998

The resistance coefficient and heat transfer performance are studied for the turbulent water flow in a smooth coiled tube having variable curvature ratios and a corrugated-coiled tube having a ratio of coil to tube diameter of 22. Experiments are carried out for the fully developed turbulent flow of water in tube coils on the uniform wall temperature condition. This work is limited to tube coils of R/a between 22 and 60 and Reynolds numbers from 13000 to 53000. The tube having a ratio of coil to tube diameter of 27 among the 3 smooth tube coils shows the best heat transfer performance. A corrugated-coiled tube(R/a=60) shows more excellent performance than a smooth coiled tub (R/a=60) at a similar curvature ratio. The friction factor f is sensitive to changes in the velocity profile caused by a temperature gradient. Allowance was made for the pressure loss in the short inlet and outlet lengths and due to the presence of the thermocouple inlet and outlet as a result of separate experimental on a straight tube. It is to be expected that the allowance at the exit will be somewhat too low because of secondary flow effects carried over from the coil.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.5
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• pp.95-106
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• 1992

Active control of acoustic noise is an application area of adaptive digital signal processing with increasingly interest along the last year. This work studies the implementation of the multichannel LMS filter and the application of this algorithm for the reduction of the noise inside a vechicle cabin using a number of 'secondary sources' drived by adaptive filtering of a reference noise source. Firstly, we propose the use of an adaptive method for the time-varient optimal convergence factor. Secondly, we propose the use of adaptive delayed inverse model to estimate the elastic-acoustic transfer function presented in vechicle cabin. The original, primary source is often periodic, with a known fundamental frequency. A suitably filtered reference signal can thus be used to drive the secondary sources. An algorithm is presented for adapting the coefficients of an FIR filter feeding such a secondary source in such a way as to minimize the output of a suitably placed microphone. In this algorithm, the coefficients of adaptive filter driving an array of secondary sources can be adapted to minimize the sum of the squares of the outputs of a number of error microphones. The multichannel LMS algorithm displays that such an algorithm is considered suitable to used for the global suppression of noise in vehicle cabin.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1975-1980
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• 2004

The three-dimensional flow in a turbine nozzle guide vane passage causes large secondary loss through the passage and increased heat transfer on the blade surface. In order to reduce or control these secondary flows, a linear cascade with a contoured endwall configuration was used and changes in the three-dimensional flow field were analyzed and discussed. Measurements of secondary flow velocity and total pressure loss within the passage have been performed by means of five-hole probes. The investigation was carried out at fixed exit Reynolds number of $4.0{\times}10^5$. The objective of this study is to document the development of the three-dimensional flow in a turbine nozzle guide vane cascade with modified endwall. The results show that the development of passage vortex and cross flow in the cascade composed of one flat and one contoured endwalls are affected by the flow acceleration which occurs in contoured endwall side. The overall loss is reduced near the flat endwall rather than contoured endwall.

• Geomechanics and Engineering
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• v.27 no.5
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• pp.481-495
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• 2021

This article assesses and estimates the progressive failure mechanism of complex pit-rest secondary toppling of slopes that are located within the vicinity of the Gas Flare Site of Refinery No. 4 in South Pars Special Zone (SPSZ), southwest Iran. The finite element numerical procedure based on the Shear Strength Reduction (SSR) technique has been employed for the stability analysis. In this regard, several step modelling stages that were conducted to evaluate the slope stability status revealed that the main instability was situated on the left-hand side (western) slope in the Flare Site. The toppling was related to the rock column-overburden system in relation to the overburden pressure on the rock columns which led to the progressive instability of the slope. This load transfer from the overburden has most probably led to the separation of the rock column and to its rotation downstream of the slope in the form of a complex pit-rest secondary toppling. According to the numerical modelling, it was determined that the Strength Reduction Factor (SRF) decreased substantially from 5.68 to less than 0.320 upon progressive failure. The estimated shear and normal stresses in the block columns ranged from 1.74 MPa to 8.46 MPa, and from 1.47 MPa to 16.8 MPa, respectively. In addition, the normal and shear displacements in the block columns ranged from 0.00609 m to 0.173 m and from 0.0109 m to 0.793 m, respectively.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11
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• pp.3116-3123
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• 1999

Current disk systems are generally designed to reduce read traffic more effectively. Hence, write traffic of the I/O workload could potentially become a bottleneck of the disk system performance. In order to overcome this problem without much cost, this paper presents using outermost-zone track of multi-zoned recording disk as a secondary disk cache. The proposed disk cache improves the disk system performance by following exploitations: speed difference between block transfer and track transfer, difference in transfer rate between outermost-zone tracks and inner tracks, reduction in the seek time caused by decreasing the number of disk cache tracks, and idle period during burst accesses. In addition, it does not waste the disk space because it allocates the caching space by the cylinder unit. The simulation results show that the proposed system improves 2.54∼3.11 times better in terms of average response time for write operations than existing disk systems..

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.4
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• pp.331-340
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• 1982

Numerical analysis is made on the turbulent heat transfer with suspension of solid particles in circular tube with constant heat flux. The mean motion of suspending particles in mixture is treated as the secondary gas flow with virtual density and viscosity. Our modeling of turbulent transport phenomena of suspension flow is based on this assumption and conventional mixing length theory. This paper gives the evidence that the mixing length models can be extended to close the governing equations for two phase turbulent flow with solid boundary at a first order level. Results on Nusselt numbers obtained by analytical treatments are compared with available experimental data and discussed. They suggest that the most important parameters of two phase turbulent heat transfer phenomena are relative particle diameter to pipe diameter, gas-solid loading ratio, and specific heat of suspending material.

• Journal of the korean Society of Automotive Engineers
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• v.14 no.2
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• pp.76-87
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• 1992

Flow and heat transfer characteristics in a horizontal electronic circuit board are studied numerically. The board has the arrays of heated blocks and the spaces between the plates and blocks are changed. Air in used as cooling fluid, of which prandt1 number is 0.7. The velocity distributions, temperature distributions, Nusselt numbers and dimensionless friction factors are obtained on the spaces between the plates and the blocks, for the cases of Rayleigh number, 0 and 10$^{5}$ . When Rayleigh number is so large, such as 10$^{5}$ , that the effect of bouyancy is not negligible, fluid friction and heat transfer is increased more than those of forced convection. This may be caused by the generation of secondary flow on the cross section of primary flow. The effect of bouyancy is of the most efficient, when the space of blocks is about block-width and the space of plates is about 1.7 times of block-height.