• Title/Summary/Keyword: New correction factor

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The Voltage-fed High Frequency Resonant Inverter Using Induction Heated Dry Steam Generator

  • Kim, Chil-Ryong;Lee, Jong-Kurl;Jung, Sang-Hwa;Mun, Sang-Pil;Kim, Sang-Don;Nakaoka, Mutsuo
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2008.05a
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    • pp.415-418
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    • 2008
  • This paper presents an innovative prototype of a new conceptual electromagnetic induction-based fluid beating appliance using voltage-fed type scries capacitor-compensated load resonant high-frequency IGBT inverter with a phase-shifted PWM and a power factor correction schemes. Its operating characteristics in steady-state are illustrated including unique features and evaluated on the basis of its computer simulation and experimental results of 10kw breadboard appliance for hot water producer and superheated steamer. The promising cost effective inverter-fed boiler appliances for electromagnetic induction-heated type fluid-heating in the pipeline systems are proposed for induction-heated boiler, super heat steamer, high temperature water producer, hot gas producer and metal catalyst heating for exhaust gas cleaning in engine, which are more suitable and acceptable for industrial, chemical, and consumer energy utilization for household and business from a practical point of view.

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An Improved PFC & Low Noise Power Supply using Quasi-Resonant Mode Hybrid IC of STR-G9600 (의사공진형 Hybrid IC STR-G9600을 이용한 저 노이즈 역률 개선형 전원 장치)

  • Lee Myung Jun;Ahn Jun Young;Shin Ho Jun;Bae Jun Sung
    • Proceedings of the KIPE Conference
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    • 2002.07a
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    • pp.233-236
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    • 2002
  • The solution for PFC(Power Factor Correction), as a regulation in energy Policy, is becoming a hot Issue in every country because of the shortage of electrical energy. Therefore, a new improved idea for PFC problem has been introduced in this study. A lot of merits, effective cost by simple circuit, reduced PCB size, lighter than reactor in the view of weight, lower level of screen noise by leakage inductance in CTV applications, have been stated by comparing to the earlier method of using a Reactor. All test results in this statement were done by using a power device of STR-G9600 series based on the real load condition of color television. furthermore, the study shows that the test results also meets the IEC-1000-3-2 class D, which regulates the PFC when input power of a set is more than 75watts. More improved PFC in other applications hopes to be implemented by using the proposed method.

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Consideration of Static-strain-dependent Dynamic Complex Modulus in Dynamic Stiffness Calculation of Viscoelastic Mount/Bushing by Commercial Finite Element Codes (점탄성 제진 요소의 복소동강성계수 산출을 위한 상용유한요소 코드 이용시 복소탄성계수의 정하중 의존성 반영 방법)

  • Kim, Kwang-Joon;Shin, Yun-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.4 s.109
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    • pp.372-379
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    • 2006
  • Little attention has been paid to static-strain-dependence of dynamic complex modulus of viscolelastic materials in computational analysisso far. Current commercial Finite Element Method (FEM) codes do not take such characteristics into consideration in constitutive equations of viscoelastic materials. Recent experimental observations that static-strain-dependence of dynamic complex modulus of viscolelastic materials, especially filled rubbers, are significant, however, require that solutions somehow are necessary. In this study, a simple technique of using a commercial FEM code, ABAQUS, is introduced, which seems to be far more cost/time saving than development of a new software with such capabilities. A static-strain-dependent correction factor is used to reflect the influence of static-strains in Merman model, which is currently the base of the ABAQUS. The proposed technique is applied to viscoelastic components of rather complicated shape to predict the dynamic stiffness under static-strain and the predictions are compared with experimental results.

Heat Transfer Correlation to Predict the Evaporation of a Water Droplet in Superheated Steam during Reflood Phase of a LOCA

  • Kim, Yoo;Ban, Chang-Hwan
    • Journal of Energy Engineering
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    • v.9 no.3
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    • pp.261-268
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    • 2000
  • A heat transfer correlation to predict the vaporization of a water droplet in highly superheated steam during a loss-of-coolant accident(LOCA) of a nuclear power plant is provided. Vaporization of liquid fuel or water droplets in superheated air or steam and subsequent interface heat transfer between a liquid droplet and superheated gas is typically correlated by way of a Nusselt number as a function of Reynolds number, Prantl number, and in some cases including mass transfer number. Presently available correlations and experimental data of the evaporation of liquid droplets in air or steam are analyzed and a new Nusselt number correlation is proposed taking Schmidt number into consideration in order to account for binary diffusion of the vapor as well, Nu$\_$f/(1+B)$\^$0.7/=2+0.53Sc$\_$f/$\^$-1/5/Re$\_$M/$\^$$\sfrac{1}{2}$/Pr$\_$f/$\^$$\sfrac{1}{3}$/ for which properties are evaluated at film condition except the density of Reynolds number evaluated at ambient condition. Diverse correlations for various combinations of liquid and gas species are put into single equation. The blowing correction factor of (1+B)$\^$0.7/ is confirmed appropriate, and a criterion to distinguish so-called high- and low-temperature condition of ambient gas is set forth.

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A new refined nonlocal beam theory accounting for effect of thickness stretching in nanoscale beams

  • Kheroubi, Boumediene;Benzair, Abdelnour;Tounsi, Abdelouahed;Semmah, Abdelwahed
    • Advances in nano research
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    • v.4 no.4
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    • pp.251-264
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    • 2016
  • In this paper, a simple and refined nonlocal hyperbolic higher-order beam theory is proposed for bending and vibration response of nanoscale beams. The present formulation incorporates the nonlocal scale parameter which can capture the small scale effect, and it considers both shear deformation and thickness stretching effects by a hyperbolic variation of all displacements across the thickness without employing shear correction factor. The highlight of this formulation is that, in addition to modeling the displacement field with only two unknowns, the thickness stretching effect (${\varepsilon}_z{\neq}0$) is also included in the present model. By utilizing the Hamilton's principle and the nonlocal differential constitutive relations of Eringen, the equations of motion of the nanoscale beam are reformulated. Verification studies demonstrate that the developed theory is not only more accurate than the refined nonlocal beam theory, but also comparable with the higher-order shear deformation theories which contain more number of unknowns. The theoretical formulation proposed herein may serve as a reference for nonlocal theories as applied to the static and dynamic responses of complex-nanobeam-system such as complex carbon nanotube system.

A simple quasi-3D sinusoidal shear deformation theory with stretching effect for carbon nanotube-reinforced composite beams resting on elastic foundation

  • Hadji, Lazreg;Zouatnia, Nafissa;Meziane, Mohamed Ait Amar;Kassoul, Amar
    • Earthquakes and Structures
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    • v.13 no.5
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    • pp.509-518
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    • 2017
  • The objective of the present paper is to investigate the bending behavior with stretching effect of carbon nanotube-reinforced composite (CNTRC) beams. The beams resting on the Pasternak elastic foundation, including a shear layer and Winkler spring, are considered. The single-walled carbon nanotubes (SWCNTs) are aligned and distributed in polymeric matrix with different patterns of reinforcement. The material properties of the CNTRC beams are estimated by using the rule of mixture. The significant feature of this model is that, in addition to including the shear deformation effect and stretching effect it deals with only 4 unknowns without including a shear correction factor. The single-walled carbon nanotubes (SWCNTs) are aligned and distributed in polymeric matrix with different patterns of reinforcement. The material properties of the CNTRC beams are assessed by employing the rule of mixture. The equilibrium equations have been obtained using the principle of virtual displacements. The mathematical models provided in this paper are numerically validated by comparison with some available results. New results of bending analyses of CNTRC beams based on the present theory with stretching effect is presented and discussed in details. the effects of different parameters of the beam on the bending responses of CNTRC beam are discussed.

A size-dependent quasi-3D model for wave dispersion analysis of FG nanoplates

  • Karami, Behrouz;Janghorban, Maziar;Shahsavari, Davood;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • v.28 no.1
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    • pp.99-110
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    • 2018
  • In this paper, a new size-dependent quasi-3D plate theory is presented for wave dispersion analysis of functionally graded nanoplates while resting on an elastic foundation and under the hygrothermaal environment. This quasi-3D plate theory considers both thickness stretching influences and shear deformation with the variations of displacements in the thickness direction as a parabolic function. Moreover, the stress-free boundary conditions on both sides of the plate are satisfied without using a shear correction factor. This theory includes five independent unknowns with results in only five governing equations. Size effects are obtained via a higher-order nonlocal strain gradient theory of elasticity. A variational approach is adopted to owning the governing equations employing Hamilton's principle. Solving analytically via Fourier series, these equations gives wave frequencies and phase velocities as a function of wave numbers. The validity of the present results is examined by comparing them with those of the known data in the literature. Parametric studies are conducted for material composition, size dependency, two parametric elastic foundation, temperature and moisture differences, and wave number. Some conclusions are drawn from the parametric studies with respect to the wave characteristics.

Buckling and free vibration analyses of nanobeams with surface effects via various higher-order shear deformation theories

  • Rahmani, Omid;Asemani, S. Samane
    • Structural Engineering and Mechanics
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    • v.74 no.2
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    • pp.175-187
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    • 2020
  • The theories having been developed thus far account for higher-order variation of transverse shear strain through the depth of the beam and satisfy the stress-free boundary conditions on the top and bottom surfaces of the beam. A shear correction factor, therefore, is not required. In this paper, the effect of surface on the axial buckling and free vibration of nanobeams is studied using various refined higher-order shear deformation beam theories. Furthermore, these theories have strong similarities with Euler-Bernoulli beam theory in aspects such as equations of motion, boundary conditions, and expressions of the resultant stress. The equations of motion and boundary conditions were derived from Hamilton's principle. The resultant system of ordinary differential equations was solved analytically. The effects of the nanobeam length-to-thickness ratio, thickness, and modes on the buckling and free vibration of the nanobeams were also investigated. Finally, it was found that the buckling and free vibration behavior of a nanobeam is size-dependent and that surface effects and surface energy produce significant effects by increasing the ratio of surface area to bulk at nano-scale. The results indicated that surface effects influence the buckling and free vibration performance of nanobeams and that increasing the length-to-thickness increases the buckling and free vibration in various higher-order shear deformation beam theories. This study can assist in measuring the mechanical properties of nanobeams accurately and designing nanobeam-based devices and systems.

Size-dependent bending analysis of FGM nano-sinusoidal plates resting on orthotropic elastic medium

  • Kolahchi, Reza;Bidgoli, Ali Mohammad Moniri;Heydari, Mohammad Mehdi
    • Structural Engineering and Mechanics
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    • v.55 no.5
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    • pp.1001-1014
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    • 2015
  • Bending analysis of functionally graded (FG) nano-plates is investigated in the present work based on a new sinusoidal shear deformation theory. The theory accounts for sinusoidal distribution of transverse shear stress, and satisfies the free transverse shear stress conditions on the top and bottom surfaces of the plate without using shear correction factor. The material properties of nano-plate are assumed to vary according to power law distribution of the volume fraction of the constituents. The size effects are considered based on Eringen's nonlocal theory. Governing equations are derived using energy method and Hamilton's principle. The closed-form solutions of simply supported nano-plates are obtained and the results are compared with those of first-order shear deformation theory and higher-order shear deformation theory. The effects of different parameters such as nano-plate length and thickness, elastic foundation, orientation of foundation orthtotropy direction and nonlocal parameters are shown in dimensionless displacement of system. It can be found that with increasing nonlocal parameter, the dimensionless displacement of nano-plate increases.

Study on Reliability of New Digital Tachograph for Traffic Accident Investigation and Reconstruction (교통사고 조사 및 재현에서 신형 전자식운행기록계의 신뢰성에 관한 연구)

  • Park, Jongjin;Joh, Geonwoo;Park, Jongchan
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.6
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    • pp.615-622
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    • 2015
  • Recently Digital-TachoGraph(DTG) was mounted mandatorily in commercial vehicles(Taxi, Bus, etc.). DTG records accurate and detailed information of the running state of vehicles related to traffic accident, such as Time, Distance, Velocity, RPM, Brake ON/OFF, GPS, Azimuth, Acceleration. Thus those standardized data can play an important role in traffic accident investigation and reconstruction. To develope the accurate and objective method using the DTG data for the reconstruction of traffic accident, we had conducted several tests such as driving test, high speed circuit test, braking test, slalom test at Korea Automobile Testing & Research Institute(KATRI), and collision test at Korea Automobile insurance repair Research and Training center(KART) with the vehicle equipped with several DTG. Development of the program which enables the reading and analysis of the DTG data was followed. In the experiments, we have found velocity error, RPM error, brake signal error and azimuth error in several products, and also non-continuous event data. The cause of these errors was deduced to be related to the correction factor, the durability of electronic parts and the algorithm.