• Title/Summary/Keyword: mechanical device

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PID control of left ventricular assist device (PID 제어기를 이용한 좌심실보조장치의 제어)

  • Jeong, Seong-Taek;Kim, Hun-Mo;Kim, Sang-Hyeon
    • Journal of Institute of Control, Robotics and Systems
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    • v.4 no.3
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    • pp.315-320
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    • 1998
  • In this paper, we present the PID control method for the controlling flow rate of highly complicated nonlinear Left Ventricular Assist Device(LVAD) with pneumatically driven mock circulatory system. Beat Rate (BR), Systole-Diastole Rate (SDR) and flow rate are used as the main variables of the LVAD system. System modeling is completed using the neural network with input variables (BR, SDR, their derivatives, actual flow) and an output valiable(actual flow). Then, as the basis of this model, we perform the simulation of PID control to predict the performance and tendency of the system and control the flow rate of LVAD system using the PID controller. The ability and effectiveness of identifying and controlling a LVAD system using the proposed algorithm will be demonstrated through computer simulation and experiments.

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Investigation on Hermeticity of Liquid Crystal Polymer Package for MEMS Based Safety Device (MEMS 기반 안전 소자에 대한 액정 폴리머 패키지의 밀폐도 연구)

  • Choi, Jinnil;Kim, Yong-Kook;Ju, Byeong-Kwon
    • Journal of Sensor Science and Technology
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    • v.24 no.5
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    • pp.287-290
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    • 2015
  • Liquid crystal polymer (LCP) is a thermoplastic polymer with superior mechanical and thermal properties. In addition, its characteristics include very low water absorption rate and possibility to apply bonding process under low temperature. In this study, LCP is utilized as a packaging material for a microelectronic system (MEMS) based safety device with suggestion of a low temperature packaging process. Highly sensitive and stable capacitive type humidity sensor is fabricated to investigate hermeticity of the packaged MEMS device.

A Development of Manufacturing Process of Wooden Footpath Block to Reuse of Wood Waste (목질폐잔재를 재활용한 목질보도블록 제조기술 개발)

  • Park, Hee-Jun
    • Journal of the Korean Wood Science and Technology
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    • v.25 no.3
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    • pp.96-104
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    • 1997
  • The objective of this research project was to develop the wooden footpath block to reuse of wood waste. Some physical and mechanical properties of the wooden block such as water absorption, thickness swelling, modulus of rupture, internal bond, density profile and impact resistance were studied. Water absorption and thickness swelling of the wooden block were greatly reduced when the wooden block was pressed inside the forming device than by conventional hot pressing. Also, Modulus of rupture and internal bond of the wooden block were increased greatly when the pressing was completed inside the forming device. The density profile of the wooden block was improved up to 93.5%, minimum to average density ratio. The wooden block manufactured in this study have excellent physical and mechanical prperties in comparison with existing wood based materials. So, these wooden blocks are applicable to footpth block or other exterior members.

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Damage Evaluation of CD-RW Drive by Drop Test and Simulation (CD-RW Drive의 낙하충격 손상평가)

  • Woo Jae Chul;Yun Ki Won;Seok Ki Young;Kim Heon Young;Kim Sang Bum
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.1 s.232
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    • pp.81-87
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    • 2005
  • A fracture of hand held device, such as radio, TV and CD-RW drive, mainly occurs due to drop situation. For CD-RW drive, the need of high reading/writing speed in conjunction with low price accelerates the fracture of the device. Computer simulation can reduce the period of development and enhance impact characteristic of device. In this study, the detailed finite element model of CD-RW drive was developed to predict the damage under drop conditions. Material property for shock absorbing damper was obtained from tensile test of raw material. A MOONEY-RIVLIN type rubber in LS-DYNA was used as the material model of damper. To assess the reliability of the developed model, drop test at 200G-2msec and 150G-10msec condition was conducted and acceleration at pick-up was compared.

A Study of Vaporization Characteristics in the Methanol Spark Ignition Engine (메탄올 스파크 점화기관의 기화특성에 관한 연구)

  • 한성빈;문성수;이성열
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.1
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    • pp.77-84
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    • 1994
  • The oil crises in 1973 and 1978 stimulated the alternative fuel research activities in many countries around the world. Among the alternative fuels, methanol is one of the highest potential fuels for transportation. Methanol has been considered for use as automotive fuel, but it has a defect of the great latent vaporization heat. Therefore, authors have made the fuel vaporizing device in order to eliminate the fuel film flow heating the mixture. This paper presents a study on the characteristics of vaporization, engine performance, and emission which result from using the fuel vaporizing device.

Seismic Behavior of Bridges with Sacrificial Energy-dissipating Devices (회생개념의 에너지소산장치의 적용에 따른 교량의 내진성능평가)

  • 김상효;이상우;김영훈
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2003.03a
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    • pp.393-400
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    • 2003
  • Various types of dampers are widely adopted to reduce the seismic damages in bridges. However, dampers may be the improper solution especially in moderate seismic regions because dampers are costly for installation and require constant maintenance during life cycle. In this study, energy-dissipating sacrificial device is proposed, which sacrifices easily substitutable bridge members and dissipates the excessive energy during seismic excitations. In turns, the inelastic behavior of sacrificial members reduces the input energy of the major members, such as piers in bridges, and may prevent the major members from serious malfunction. A simplified mechanical model is developed to represent the behavior of sacrificial devices installed in a bridge. The hysteresis energy of piers is analyzed to certify performance of device under seismic loads applied to this mechanical model. The results from this study show that the proposed sacrificial energy-dissipating device can decrease excessive hysteresis energy and reduce the damage of piers under seismic excitation. Therefore, economical enhancement of the seismic performance of bridges may be possible by employing the proposed sacrificial energy-dissipating devices.

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A Study on the Culture Media Control of Smart Plant Cultivator (스마트 식물 재배기의 양액 제어에 관한 연구)

  • Jeong, Sang-Hwa;Yoon, Chung-Man
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.4
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    • pp.87-92
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    • 2019
  • In this paper, a closed hydroponics device was designed and fabricated to grow and harvest plants in a small space for safe consumption, which enables horticultural activities that are difficult to perform due to space constraints from urbanization. This device also aimed to minimize the air pollution of crops. To obtain data for the optimal growth conditions for crops in this intelligent plant-growing system, sensors were used to measure and control the growth conditions. To investigate the optimal growth conditions, blue lettuce and crown daisy were selected as representative crops. The growth rates were comparatively analyzed through four experiments for each plant. This hydroponics device was used to collect data on growth rates that are altered depending on cultivation conditions, which can then be used to study methods to control the growth rate of crops.

Development of RTOS Based LinuxCNC 3-axis Control System with EhterCAT Communication (RTOS기반 LinuxCNC에서 EtherCAT 통신이 적용된 3축 CNC 제어 시스템 개발)

  • Kang, Y.S.;Yu, G.S.;Tae, B.H.;Choi, I.H.;Lee, J.W.;Seo, Y.H.;Kim, Byeong Hee
    • Journal of Industrial Technology
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    • v.40 no.1
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    • pp.19-23
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    • 2020
  • In this paper, we proposed a PC-based CNC control system using EtherCAT-based servo drive and I/O device. The default communication of LinuxCNC is a parallel port, and data processing with high bandwidth is impossible. However, it is possible to apply various bandwidth devices through the application of EtherCAT, one of the industrial Ethernet communications with high bandwidth. Therefore, the hardware control method of LinuxCNC was applied through EtherCAT communication from the existing parallel port. Finally, through HAL configuration, I/O device operation check and 3-axis motion control proved the LinuxCNC system with EtherCAT.

Facile Chemical Growth of Cu(OH)2 Thin Film Electrodes for High Performance Supercapacitors (간단한 화학적 합성을 통한 고성능 슈퍼캐패시터용 수산화 구리 전극)

  • Patil, U.M.;Nam, Min Sik;Shinde, N.M.;Jun, Seong Chan
    • KEPCO Journal on Electric Power and Energy
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    • v.1 no.1
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    • pp.175-180
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    • 2015
  • A facile soft chemical synthesis route is used to grow nano-buds of copper hydroxide [$Cu(OH)_2$] thin films on stainless steel substrate[SS]. Besides different chemical methods for synthesis of $Cu(OH)_2$ nanostructure, the chemical bath deposition (CBD) is attractive for its simplicity and environment friendly condition. The structural, morphological, and electro-chemical properties of $Cu(OH)_2$ thin films are studied by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) measurement techniques. The results showed that, facile chemical synthesis route allows to form the polycrystalline, granular nano-buds of $Cu(OH)_2$ thin films. The electrochemical properties of $Cu(OH)_2$ thin films are studied in an aqueous 1 M KOH electrolyte using cyclic voltammetry. The sample exhibited supercapacitive behavior with $340Fg^{-1}$ specific capacitance. Moreover, electrochemical capacitive measurements of $Cu(OH)_2/SS$ electrode exhibit a high specific energy and power density about ${\sim}83Wh\;kg^{-1}$ and ${\sim}3.1kW\;kg^{-1}$, respectively, at $1mA\;cm^{-2}$ current density. The superior electrochemical properties of copper hydroxide ($Cu(OH)_2/SS$) electrode with nano-buds like structure mutually improves pseudocapacitive performance. This work evokes scalable chemical synthesis with the enhanced supercapacitive performance of $Cu(OH)_2/SS$ electrode in energy storage devices.

Hydrothermally Synthesis Nanostructure ZnO Thin Film for Photocatalysis Application (수열합성법으로 합성된 산화아연 나노 구조 박막의 광촉매적 응용)

  • Shinde, N.M.;Nam, Min Sik;Patil, U.M.;Jun, Seong Chan
    • KEPCO Journal on Electric Power and Energy
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    • v.2 no.1
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    • pp.97-101
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    • 2016
  • ZnO has nanostructured material because of unique properties suitable for various applications. Amongst all chemical and physics methods of synthesis of ZnO nanostructure, the hydrothermal method is attractive for its simplicity and environment friendly condition. Nanostructure ZnO thin films have been successfully synthesized on fluorine doped tin oxide (FTO) substrate using hydrothermal method. A possible growth mechanism of the various nanostructures ZnO is discussed in schematics. The prepared materials were characterized by standard analytical techniques, i.e., X-ray diffraction (XRD) and Field-emission scanning electron microscopy (SEM). The XRD study showed that the obtained ZnO nanostructure thin films are in crystalline nature with hexagonal wurtzite phase. The SEM image shows substrate surface covered with nanostructure ZnO nanrod. The UV-vis absorption spectrum of the synthesized nanostructure ZnO shows a strong excitonic absorption band at 365 nm which indicate formation nanostructure ZnO thin film. Photoluminescence spectra illustrated two emission peaks, with the first one at 424 nm due to the band edge emission of ZnO and the second broad peak centered around 500 nm possibly due to oxygen vacancies in nanostructure ZnO. The Raman measurements peaks observed at $325cm^{-1}$, $418cm^{-1}$, $518cm^{-1}$ and $584cm^{-1}$ indicated that nanostrusture ZnO thin film is high crystalline quality. We trust that nanostructure ZnO material can be effectively will be used as a highly active and stable phtocatalysis application.