• Title/Summary/Keyword: Arc state

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Development of Module Type 20kW Plasma Power Supply for Magnetron Sputter (마그네트론 스퍼터용 20kW급 플라즈마 전원장치 개발)

  • Seo, Kwang-Duk;Kim, Sang-Hoon
    • Journal of Industrial Technology
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    • v.27 no.A
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    • pp.157-162
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    • 2007
  • This paper describes a power supply aimed at the production of plasma and its control method for a magnetron sputter in thin film coating process of PVD(Physical Vapor Deposition). Plasma load changes its impedance characteristic easily according to operating conditions and frequently produces electric arc. So. in this paper, a plasma power supply with improved output control performance in the transient state for the plasma load is presented. Also, it includes a strategy that can detect arc rapidly and reduce arc energy effectively into a load. The validity of the proposed power supply through experimentation on 20kW system was proved.

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Large deflections of variable-arc-length beams under uniform self weight: Analytical and experimental

  • Pulngern, Tawich;Halling, Marvin W.;Chucheepsakul, Somchai
    • Structural Engineering and Mechanics
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    • v.19 no.4
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    • pp.413-423
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    • 2005
  • This paper presents the solution of large static deflection due to uniformly distributed self weight and the critical or maximum applied uniform loading that a simply supported beam with variable-arc-length can resist. Two analytical approaches are presented and validated experimentally. The first approach is a finite-element discretization of the span length based on the variational formulation, which gives the solution of large static sag deflections for the stable equilibrium case. The second approach is the shooting method based on an elastica theory formulation. This method gives the results of the stable and unstable equilibrium configurations, and the critical uniform loading. Experimental studies were conducted to complement the analytical results for the stable equilibrium case. The measured large static configurations are found to be in good agreement with the two analytical approaches, and the critical uniform self weight obtained experimentally also shows good correlation with the shooting method.

Using GIS to Determine the Best Areas for Displacement from Khartoum State to Other States in Sudan

  • Eihab A. M. Osman
    • International Journal of Computer Science & Network Security
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    • v.24 no.1
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    • pp.23-30
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    • 2024
  • This study tries clarify the process of making decisions with geographic information systems and how to choose the best place for Khartoum State displaced people to relocate to in order to be closer to cheaper places with access to commodities and services. For network analysis, use a unique model. The network analysis tool was dependent on the following information: availability of goods and services, cheap cost, and proximity to the state of Khartoum.in choosing the best state. The study came to the conclusion that, in terms of accessibility, affordability, and availability of products and services, Gezira State is the best state for people who have been displaced from Khartoum State.When developing a new model, we recommend that all GIS users apply the theories of spatial analysis.

Analytical Solution for Transient Temperature Distribution in Fillet Arc Welding (필릿 용접 공정에서 온도 분포 예측을 위한 해석적 모델)

  • 정선국;조형석
    • Journal of Welding and Joining
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    • v.13 no.2
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    • pp.68-81
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    • 1995
  • This paper presents an analytical solution to predict the transient temperature distribution in fillet arc welding. The analytical solution is obtained by solving a transient three -dimensional heat conduction equation with convection boundary conditions on the surfaces of an infinite plate with finite thicknesses, and mapping an infinite plate onto the fillet weld geometry with energy equation. The electric arc heat input on fillet weld and on infinite plate is assumed to have a traveling bivariate Gaussian distribution. To check the validity of the solution, GTA and FCA welding experiments were performed under various welding conditions. The actual isotherms of the weldment cross - sections at various distances from the arc start point are compared with those of simulation result. As the result shows a satisfactory accuracy, this analytical solution can be used to predict the transient temperature distribution in the fiIIet weld of finite thickness under a moving bivariate Gaussian distributed heat source. The simplicity and short calculation time of the analytical solution provides rationales to use the analytical solution for modeling the welding control systems or for an optimization tool of welding process parameters.

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Medium Voltage Power Supply with Enhanced Ignition Characteristics for Plasma Torches

  • Jung, Kyung-Sub;Suh, Yong-Sug
    • Journal of Power Electronics
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    • v.11 no.4
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    • pp.591-598
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    • 2011
  • This paper investigates a power supply of medium voltage with enhanced ignition characteristics for plasma torches. A series resonant half-bridge topology is presented as a suitable ignition circuitry. The ignition circuitry is integrated into the main power conversion system of a multi-phase staggered three-level dc-dc converter with a diode front-end rectifier. A plasma torch rated at 3MW, 2kA and having a physical size of 1m is selected to be the high enthalpy source for a waste disposal system. The steady-state and transient operations of a plasma torch are simulated. The parameters of a Cassie-Mary arc model are calculated based on 3D magneto-hydrodynamic simulations. The circuit simulation waveform shows that the ripple of the arc current can be maintained within ${\pm}10%$ of its rated value under the presence of a load disturbance. This power conversion configuration provides a high enough ignition voltage, around 5KA, during the ignition phase and high arc stability under the existence of arc disturbance noise resulting in a high-performance plasma torch system.

Numerical Simulation of Bubble and Pore Generations by Molten Metal Flow in Laser-GMA Hybrid Welding (레이저-GMA 하이브리드 용접에서 유동에 의한 기포 및 기공 형성 해석)

  • Cho, Won-Ik;Cho, Jung-Ho;Cho, Min-Hyun;Lee, Jong-Bong;Na, Suck-Joo
    • Journal of Welding and Joining
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    • v.26 no.6
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    • pp.67-73
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    • 2008
  • Three-dimensional transient simulation of laser-GMA hybrid welding involving multiple physical phenomena is conducted neglecting the interaction effect of laser and arc heat sources. To reproduce the bubble and pore formations in welding process, a new bubble model is suggested and added to the established laser and arc welding models comprehending VOF, Gaussian laser and arc heat source, recoil pressure, arc pressure, electromagnetic force, surface tension, multiple reflection and Fresnel reflection models. Based on the models mentioned above, simulations of laser-GMA hybrid butt welding are carried out and besides the molten pool flow, top and back bead formations could be observed. In addition, the laser induced keyhole formation and bubble generation duo to keyhole collapse are investigated. The bubbles are ejected from the molten pool through its top and bottom regions. However, some of those are entrapped by solid-liquid interface and remained as pores. Those bubbles and pores are intensively generated when the absorption of laser power is largely reduced and consequently the full penetration changes to the partial penetration.

Analysis of the hot gas flow field in a interrupter of UHV GCB (초고압 GCB 소호부내의 열가스 유동해석)

  • Song, K.D.;Park, K.Y.;Lee, B.Y.
    • Proceedings of the KIEE Conference
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    • 1999.07a
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    • pp.372-375
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    • 1999
  • This paper presents an arc(hot-gas flow field) analysis method in GCB. This method includes the Lorentz's force due to magnetic field, turbulent viscous effect and radiation heat transfer which are indispensable to the analysis of hot-gas flow. To verify the applicability of the Proposed method, steady state hot-Eas flow analysis within a simplified interrupter has been carried out. Inlet boundary pressure values were assumed to be 9.0atm and 12.0atm. For each inlet boundary condition, three cases of hot-gas flow field analyses were performed according to the values of arc currents which were assumed to be D.C 0.6kA. 1.0kA and 2.0kA. The results revealed that the arc radius at nozzle throat has been concentrated by increasing the pressure of nozzle upstream and that the maximum temperature of arc core has been decreased along to nozzle exit and the high temperature lesion come to be wide in nozzle downstream. From these results, it is confirmed that the proposed method will be applicable to predict the large current interruption capability of GCB.

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Basic Welding Characteristics by Nd-YAG Laser Beam on AH32 (선급강재의 레이저 용접특성에 관한 기초실험 - HYBRID 용접시 LASER-ARC거리 변화에 따른 용융특성 변화에 관한 실험)

  • Bang, Ban-Sur;Joo, Sung-Min;Kim, Young-Pyo;Kim, Hyung;Katayama, Seiji
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2003.05a
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    • pp.279-283
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    • 2003
  • As the state of the art in recent years Laser-Arc Hybrid welding is tried actively because of its various economical and technical advantages. In this study, melting tendencies according to the variation of laser-arc distance are investigated in case of YAG laser-TIG Hybrid welding process of AH32 ship structural steel. Nd-YAG laser with a laser beam power of 3KW is used and varied laser-arc distance 0mm to 10mm with fixing the TIG current as l00A. There is certain distance between laser and TIG elecrode to improve welding heat input and also increase the penetration.

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The effect of individualization of fiberglass posts using bulk-fill resin-based composites on cementation: an in vitro study

  • Lins, Rodrigo Barros Esteves;Cordeiro, Jairo Matozinho;Rangel, Carolina Perez;Antunes, Thiago Bessa Marconato;Martins, Luis Roberto Marcondes
    • Restorative Dentistry and Endodontics
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    • v.44 no.4
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    • pp.37.1-37.10
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    • 2019
  • Objectives: This study evaluated the bond strength of various fiberglass post cementation techniques using different resin-based composites. Materials and Methods: The roots from a total of 100 bovine incisors were randomly assigned to 5 treatment groups: G1, post + Scotchbond Multi-Purpose (SBMP) + RelyX ARC luting agent; G2, relined post (Filtek Z250) + SBMP + RelyX ARC; G3, individualized post (Filtek Z250) + SBMP; G4, individualized post (Filtek Bulk-Fill) + SBMP; G5, individualized post (Filtek Bulk-Fill Flow) + SBMP. The samples were subjected to the push-out (n = 10) and pull-out (n = 10) bond strength tests. Data from the push-out bond strength test were analyzed using 2-way analysis of variance (ANOVA) with the Bonferroni post hoc test, and data from the pull-out bond strength test were analyzed using 1-way ANOVA. Results: The data for push-out bond strength presented higher values for G2 and G5, mainly in the cervical and middle thirds, and the data from the apical third showed a lower mean push-out bond strength in all groups. No significant difference was noted for pull-out bond strength among all groups. The most frequent failure modes observed were adhesive failure between dentine and resin and mixed failure. Conclusions: Fiberglass post cementation using restorative and flowable bulk-fill composites with the individualization technique may be a promising alternative to existing methods of post cementation.