• Title/Summary/Keyword: hybrid process

Search Result 1,930, Processing Time 0.029 seconds

Preparation and Properties of Inorganic-organic Hybrid $Li^+$ Ion Conductor by Sol-gel Process

  • Nishio, Keishi;Miyazawa, Tsutomu;Watanabe, Yuichi;Tsuchiya, Toshio
    • The Korean Journal of Ceramics
    • /
    • v.7 no.1
    • /
    • pp.1-5
    • /
    • 2001
  • Inorganic-organic hybrid Li$^+$ ion conductors were prepared by the sol-gel process. Tetramethyl orthosilicate (TMOS), polyethylene glycol 200 (PEG$_200$) and lithium bis (trifluoro-methylsulfony) imide were used as raw materials and $H_2O$ was used as a solvent. Hybrid Li$^+$ ion conductor prepared by the sol-gel process showed very high ion conductivities of log${\sigma}_R.T$(S/cm)=-3.73, log${\sigma}_60$(S/cm)=-3.00 at room temperature and $60^{\circ}C$, respectivery. Decomposition voltage was 3.1 V.

  • PDF

Reliability Problem Solving Through Root Cause Analysis (근본원인분석을 이용한 신뢰성 문제 해결)

  • Jeong, Hai Sung
    • Journal of Applied Reliability
    • /
    • v.16 no.1
    • /
    • pp.71-77
    • /
    • 2016
  • Purpose: Root cause analysis (RCA) refers to any systematic process that identifies the causes that contribute to a focus event. The immediate cause of a focus event is often a symptom of underlying causes and may not truly identify the root causes that should be identified and addressed. Currently many RCA tools are available. Different investigators use different RCA tools on different issues. No standardized or commonly agreed way to analyse root causes exists. The purpose of this study is to propose the methodology of RCA process commonly useable for various issues. Methods: The methodology of RCA process is produced based on the hybrid RCA tools. The effectiveness assessment matrix of actions through the root cause candidates is presented. Results: No single RCA technique proposed has so far covered all necessary aspects. A hybrid approach which combines the best features of various techniques is proposed. The effectiveness assessment matrix helps us to identify the root cause to correct or eliminate system vulnerabilities effectively. Conclusion: This hybrid approach and effectiveness assessment matrix can provide guidance of RCA process across many industries and situations.

Development of New Rapid Prototyping System Performing both Deposition and Machining (II) (적층과 절삭을 복합적으로 수행하는 새로운 개념의 판재 적층식 쾌속 시작 시스템의 개발(II) - 공정계획 시스템 -)

  • Heo, Jeong-Hun;Lee, Geon-U
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.24 no.9 s.180
    • /
    • pp.2235-2245
    • /
    • 2000
  • The necessity of using rapid prototyping(RP) for short-run manufacturing is continuously driving a development of a cost-effective technique that will produce completely-finished quality parts in a very short time. To meet these demands, the improvements in production speed, accuracy, materials, aid cost are crucial. Thus, a new hybrid-RP system performing both deposition and machining in a station is proposed. For the new hybrid RP process to maintain the same degree of process automation as in currently available processes like SLA or FDNI, a sophisticated process planning system is developed. In the process planner, CAD models(STEP AP203) are partitioned into 3D manufacturable volumes called 'Ueposition feature segment"(DFS) after machining features called "machining feature segmenf'(MFS) are extracted from the initial CAD model. Once MFS and DFS are identified, the process planner arranges them into a chain of processes and automatically generates machining information for each DFS and MFS. The goal of this paper is to present a framework for a process planning system for hybrid RP processes and to outline the geometric algorithms involved in developing such an environment.

Effects of Metallic Silicon on the Synthsis of β-SiC Powders by a Carbothermal Reduction Using SiO2-C Hybrid Precursor Fabricated by a Sol-gel Process (솔-젤 공정으로 제조된 SiO2-C 복합 전구체를 사용하여 열탄소환원법에 의한 β-SiC 분말 합성에 금속 Si 첨가가 미치는 영향)

  • Jo, Yung-Chul;Youm, Mi-Rae;Yun, Sung-Il;Cho, Gyoung-Sun;Park, Sang-Whan
    • Journal of the Korean Ceramic Society
    • /
    • v.50 no.6
    • /
    • pp.402-409
    • /
    • 2013
  • The objective of this study was to develop a synthesis process for ${\beta}$-SiC powders to reduce the synthesis temperature and to control the particle size and to prevent particle agglomeration of the synthesized ${\beta}$-SiC powders. A phenol resin and TEOS were used as the starting materials for the carbon and Si sources, respectively. $SiO_2$-C hybrid precursors with various C/Si mole ratios were fabricated using a conventional sol-gel process. ${\beta}$-SiC powders were synthesized by a carbothermal reduction process using $SiO_2$-C hybrid precursors with various C/Si mole ratios (1.6 ~ 2.5) fabricated using a sol-gel process. In this study, the effects of excess carbon and the addition of Si powders to the $SiO_2$-C hybrid precursor on the synthesis temperature and particle size of ${\beta}$-SiC were examined. It was found that the addition of metallic Si powders to the $SiO_2$/C hybrid precursor with excess carbon reduced the synthesis temperature of the ${\beta}$-SiC powders to as low as $1300^{\circ}C$. The synthesis temperature for ${\beta}$-SiC appeared to be reduced with an increase of the C/Si mole ratio in the $SiO_2$-C hybrid precursor by a direct carburization reaction between Si and excess carbon.

Development of Electrical and Oil Heater for Energy Saving (에너지 절감형 전기 유류 겸용 온풍기 개발)

  • Chung, Sung-Won;Kim, Dong-Keon;Gong, Sang-Ho
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.10 no.5
    • /
    • pp.38-43
    • /
    • 2011
  • This study was carried out to evaluate the structural stability of hybrid type fan heater. The evaluation of structural safety of hybrid fan heater was conducted by using Ansys Workbench and CFX-11 under the design condition. The hybrid fan heater was operated by heat transfer for heat source supplied from electric heater and combustion gas. According to result of structural analysis, the maximum equivalent stress of hybrid fan heater was 150MPa when the temperature of heat transfer fluids was $150^{\circ}C$. It was found that the hybrid fan was structurally safe because the value of maximum equivalent stress was smaller than that of yield stress of the material.

Fabrication of a Micro Die by LIGA Process and Hybrid Powder Extrusion Process of Micro-spur Gear (LIGA 공정을 이용한 초소형 스퍼기어 금형 제작 및 하이브리드 분말 압출성형)

  • Lee, K.H.;Hwang, D.W.;Kim, J.H.;Jang, S.S.;Kim, B.M.
    • Transactions of Materials Processing
    • /
    • v.19 no.6
    • /
    • pp.352-356
    • /
    • 2010
  • This paper was designed to fabricate the micro-spur gear by the LIGA and hybrid powder extrusion process. It is important to manufacture a micro-die with a high aspect ratio and determine appropriate extrusion conditions for a microforming. Ni has been used to fabricate micro-dies. LIGA process was capable to produce micro-extrusion dies with close tolerance, longer bearing length and adequate surface quality. Superplastic Al-78Zn powders have the great advantage in achieving deformation under low stresses and exhibiting good micro-formability with average strain rate raging from $10^{-3}$ to $10^{-2} s^{-1}$ and constant temperature ranging from 503 to 563K. Al-78Zn powders were compacted into a cylindrical shape ($\Phi3\times$h10mm) under compressive force of 10kN and, subsequently, the compacted powders were extruded by the hybrid powder extrusion process controlling of the temperature holing time for a improvement on formability of Al-22Zn powder. Micro-extrusion has succeeded in forming micro-gear shafts.

A Study on the Hybrid-ECAP Process to Produce Ultra-Fine Materials (초미세 결정립 조직을 만들기 위한 복합전단가공법에 관한 연구)

  • Lee, Ju-Hyun;Lee, Jin-Ho
    • Journal of the Korea Institute of Military Science and Technology
    • /
    • v.11 no.4
    • /
    • pp.83-91
    • /
    • 2008
  • The development of the equal channel angular pressing(ECAP) process in metals has recently provided a feasible solution to produce ultra-fine or nano-grained bulk materials with tailored material properties. However, ECAP process is difficult to scale up commercially due to requirements of an excessive load. In this paper, a new Hybrid-ECAP process with torsional die is considered to obtain materials of ultra-fine grain structure under low forming load. An upper bound analysis and numerical simulation (DEFORM 3D, a commercial FEM code) are carried out on the torsional die. By the upper bound analysis, analytical expression for the compression force and rotation speed are obtained. By the FEM analysis, the distribution of strain, stress and deformation are obtained. These results show that the Hybrid-ECAP is a useful process because this process can obtain the homogeneous deformations with relatively low forming load. Additionally, due to decreased forming load, die life can be improve.

A Hybrid Approach to Statistical Process Control

  • Giorgio, Massimiliano;Staiano, Michele
    • International Journal of Quality Innovation
    • /
    • v.5 no.1
    • /
    • pp.52-67
    • /
    • 2004
  • Successful implementation of statistical process control techniques requires for operational definitions and precise measurements. Nevertheless, very often analysts can dispose of process data available only by linguistic terms, that would be a waste to neglect just because of their intrinsic vagueness. Thus a hybrid approach, which integrates fuzzy set theory and common statistical tools, sounds useful in order to improve effectiveness of statistical process control in such a case. In this work, a fuzzy approach is adopted to manage linguistic information, and the use of a Chi-squared control chart is proposed to monitor process performance.

Autonomous Navigation Motion Control of Mobile Robots using Hybrid System Control Method (하이브리드 시스템 제어 방법을 이용한 이동로봇의 자율 추행 동작제어)

  • Lee, Yong-Mi;Im, Mi-Seop;Im, Jun-Hong
    • The Transactions of the Korean Institute of Electrical Engineers D
    • /
    • v.51 no.5
    • /
    • pp.182-189
    • /
    • 2002
  • This paper presents a framework of hybrid dynamic control systems for the motion control of wheeled mobile robot systems with nonholonomic constraints. The hybrid control system has the 3-layered hierarchical structure: digital automata for the higher process, mobile robot system for the lower process, and the interface as the interaction process between the continuous dynamics and the discrete dynamics. In the hybrid control architecture of mobile robot, the continuous dynamics of mobile robots are modeled by the switched systems. The abstract model and digital automata for the motion control are developed. In high level, the discrete states are defined by using the sensor-based search windows and the reference motions of a mobile robot in low level are specified in the abstracted motions. The mobile robots can perform both the motion planning and autonomous maneuvering with obstacle avoidance in indoor navigation problem. Simulation and experimental results show that hybrid system approach is an effective method for the autonomous maneuvering in indoor environments

Design and Production of Hybrid Type Center Plate for Molten Carbonate Fuel Cell (용융탄산염 연료전지용 하이브리드 타입 센터 플레이트의 설계 및 제작)

  • Lee, C.H.;Ryu, S.M.;Yang, D.Y.;Kang, D.W.;Chang, I.G.;Lee, T.W.
    • Transactions of Materials Processing
    • /
    • v.20 no.4
    • /
    • pp.273-278
    • /
    • 2011
  • Employing the TRIZ problem solving technique, a hybrid-type center plate for the molten carbonate fuel cell(MCFC) was developed for the purpose of improving gas sealing and maintenance. The manufacturing method of the hybrid-type center plate was divided into a trimming operation and a two-step bending process. In the latter, a modified punch shape was used to reduce springback. Using finite element(FE) simulations, bending stresses in the thickness and the in-plane directions were computed and the bending conditions were optimized. The optimized results of the two-step bending process were used as a basis for the design of the trimming process of the hybrid-type center plate. Finally, the external manifold-type center plate and the hybrid-type center plate were fabricated using a die set that accounts for the optimized conditions. It was found that the numerical simulation results were in good agreement with the experiments.