• Title/Summary/Keyword: Linear Guide

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EXPERIMENT AND SIMULATION OF A WIND-DRIVEN REVERSE OSMOSIS DESALINATION SYSTEM

  • Park, Sang-Jin;Clark C.K. Liu
    • Water Engineering Research
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    • v.4 no.1
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    • pp.1-17
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    • 2003
  • A mathematical model was developed to simulate the performance of a prototype wind-powered reverse osmosis desalination system. The model consists of two sub-models operated in a series. The first sub-model is the wind-energy conversion sub-model, which has wind energy and feed water as its input and pressurized feed water as its output. The second sub-model is a reverse osmosis (RO) process sub-model, with pressurized feed water as its input and the flow and salinity of the product water or permeate as its output. Model coefficients were determined based on field experiments of a prototype wind powered RO desalination system of the University of Hawaii, from June to December 2001. The mathematical model developed by this study predicts the performance of wind-powered RO desalination systems under different design conditions. The system optimization is achieved using a linear programming approach. Based on the results of system optimization, a design guide is prepared, which can be used by both manufacturer and end-user of the wind-driven reverse osmosis system.

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Fuzzy Preference Based Interactive Fuzzy Physical Programming and Its Application in Multi-objective Optimization

  • Zhang Xu;Huang Hong-Zhong;Yu Lanfeng
    • Journal of Mechanical Science and Technology
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    • v.20 no.6
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    • pp.731-737
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    • 2006
  • Interactive Fuzzy Physical Programming (IFPP) developed in this paper is a new efficient multi-objective optimization method, which retains the advantages of physical programming while considering the fuzziness of the designer's preferences. The fuzzy preference function is introduced based on the model of linear physical programming, which is used to guide the search for improved solutions by interactive decision analysis. The example of multi-objective optimization design of the spindle of internal grinder demonstrates that the improved preference conforms to the subjective desires of the designer.

Development of On-machine Flatness Measurement Method (평면도 기상 측정 방법 개발)

  • 장문주;홍성욱
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.3
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    • pp.187-193
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    • 2003
  • This paper presents an on-machine measurement method of flatness error fur surface machining processes. There are two kinds of on-machine measurement methods available to measure flatness errors in workpieces: i.e., surface scanning method and sensor scanning method. However, motion errors are often engaged in both methods. This paper proposes an idea to realize a measurement system of flatness errors and its rigorous application for estimation of motion errors of the positioning system. The measurement system is made by modifying the straightness measurement system, which consists of a laser, a CCD camera and processing system, a sensor head, and some optical units. The sensor head is composed of a retroreflector, a ball and ball socket, a linear motion guide unit and adjustable arms. The experimental .results show that the proposed method is useful to identify flatness errors of machined workpieces as well as motion errors of positioning systems.

Implant Fixture Installation in the Posterior Maxilla Using a Tooth-supported Surgical Template Based on Computer Assisted Treatment Planning (컴퓨터 보조 기반 치아 지지 서지컬 템프레이트를 이용한 상악구치부 임플란트 식립)

  • Kim, Soung Min;Kim, Myung Joo;Lee, Jee Ho;Myoung, Hoon;Lee, Jong Ho;Kim, Myung Jin
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.35 no.6
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    • pp.381-389
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    • 2013
  • Two patients with partial edentulous maxilla were scheduled to undergo installation of implant fixtures using a tooth-supported surgical template based on computer assisted treatment planning. After 3-dimensional (3D) computed tomographic scanning was transferred to the OnDemand3D (Cybermed Co., Seoul, Korea) software program for virtual planning, fixtures of MK III Groovy RP implant of the Br${\aa}$nemark System (Nobel Biocare AB Co., G$\ddot{o}$teborg, Sweden) was installed using the In2Guide (CyberMed Co., Seoul, Korea) tooth-supported surgical template with a Quick Guide Kit (Osstem Implant Co., Seoul, Korea) system in the posterior maxilla of each patient. Sinus floor elevation with a xenogenic bone graft procedure was also performed simultaneously in one patient. Fixture installations were completed successfully without complications, such as sinus mucosa perforation, bony bleedings, fenestrations, or others. During the last two-year follow-up period after prosthetics delivery, each implant was found to be fine with no other minor complications. The entire procedures are reported and the literatures on use of tooth-supported surgical template was reviewed.

Effect of the Acceleration and Deceleration on the Dynamic Characteristics of an Air Stage (에어 스테이지의 동적 특성에 미치는 가속도 및 감속도의 영향)

  • Park, Sang Joon;Lee, Jae Hyeok;Park, Sang-Shin;Kim, Gyu Ha
    • Tribology and Lubricants
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    • v.36 no.1
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    • pp.39-46
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    • 2020
  • Air stages are usually applied to precision engineering in sectors such as the semiconductor industry owing to their excellent performance and extremely low friction. Since the productivity of a semiconductor depends on the acceleration and deceleration performance of the air stage, many attempts have been made to improve the speed of the stage. Even during sudden start or stop sequences, the stage should maintain an air film to avoid direct contact between pad and the rail. The purpose of this study is to quantitatively predict the dynamic behavior of the air stage when acceleration and deceleration occur. The air stage is composed of two parts; the stage and the guide-way. The stage transports objects to the guideway, which is supported by an externally pressurized gas bearing. In this study, we use COMSOL Multiphysics to calculate the pressure of the air film between the stage and the guide-way and solve the two-degree-of-freedom equations of motion of the stage. Based on the specified velocity conditions such as the acceleration time and the maximum velocity of stage, we calculate the eccentricity and tilting angle of the stage. The result shows that the stiffness and damping of the gas bearing have non-linear characteristics. Hence, we should consider the operating conditions in the design process of an air stage system because the dynamic behavior of the stage becomes unstable depending on the maximum velocity and the acceleration time.

Miniature PZT actuated microdrive for chronic neural recording in small animals (신경신호 기록을 위한 PZT기반 마이크로 드라이브)

  • Park, Sang-Kyu;Park, Hyun-Jun;Park, Suk-Ho;Kim, Byung-Kyu;Shin, Hee-Sub;Lee, Suk-Chan;Kim, Hui-Su;Kim, Eun-Tai
    • Proceedings of the KIEE Conference
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    • 2005.10b
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    • pp.38-40
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    • 2005
  • Microdrive with high precision and light mass enough to install on mouse head was fabricated for recording the reliable signal of neuron cell to understand the brain study. The proposed microdrive has three H-form PZT actuators and its guide structure. The microdrive operation principle is based on the well known inchworm principle. The synchronization of three PZT actuators is able to produce the linear motion along the guide structure. Our proposed microdrive has a precise accuracy of about 100nm and a long stroke of about 5mm. The electrode which is used for the recording of the action potential of the neuron cell was fixed at one of PZT actuators. The proposed microdrive was suited to acquisition of signals from in vivo extra-cellular single-unit recoding. On the condition of the anesthetized mouse, the single-unit signals could be recorded by using the proposed microdrive. In addition, applying the PZT microdrive to an alert mouse, we try to implant it on a mouse brain skull to explore single neuron firing.

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Development of machining system for ultra-precision aspheric lens mold (초정밀 비구면 렌즈 금형가공시스템 개발)

  • Baek, Seung-Yub;Lee, Ha-Sung;Kang, Dong-Myeong
    • Design & Manufacturing
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    • v.2 no.1
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    • pp.33-38
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    • 2008
  • As consumer in optics, electronics, aerospace and electronics industry grow, the demand for ultra precision aspherical surface lens increases higher. Precision turning with single-diamond tools has a long history of development for fabrication of optical quality surfaces since the advent of aerostatic rotary spindles and precise linear motion guide ways. To enhance the precision and productivity of ultra precision aspherical surface micro lens, the following specification of ultra precision grinding system is required: the highest rotational speed of the grinder is 100,000rpm and its turning accuracy is $0.1{\mu}m$, positioning accuracy is $0.1{\mu}m$. The development process of the grinding system for the ultra precision aspherical surface micro lens for optoelectronics industry is introduced. In the work reported in this paper, an intelligent grinding system for ultra precision aspherical surface machining was designed by considering the factors affecting the surface roughness and profiles accuracy. An aerostatic form was adopted to build the spindle of the workpiece and the spindle of grinder and ultra precision LM guide way was adopted in this system. And this paper deals with mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and spherical lens of BK7. It results was that a form accuracy of $0.6{\mu}m$ P-V and a surface roughness of $0.006{\mu}m$ Rmax.

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A Study on Morphology and Behavior of the Sapsaree : A Korean native dog (Canis familiaris)

  • Han, Kook-Il;Alam, Mahboob;Lee, Yun-Mi;Lee, Dong-Hoon;Ha, Ji-Hong;Kim, Jong-Joo
    • Journal of Animal Science and Technology
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    • v.52 no.6
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    • pp.481-490
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    • 2010
  • This study was conducted to characterize the morphological and behavior patterns of Sapsaree dogs. The population (n=8,256) has been constructed since 1990 over 12 generations and managed at the Sapsaree Breeding Research Institute, Gyeongsan, Gyeongbuk province. Eighteen morphological and seven behavioral traits were investigated for 882 individuals. Linear models were applied for each trait by fitting sex, season of birth, hair color or test age. The averages of body weight, body length, body height, and depth of chest were $20.5{\pm}2.4\;kg$, $57.3{\pm}4.2\;cm$, $52.1{\pm}3.6\;cm$, and $21.1{\pm}2.4\;cm$, respectively. Males had greater estimated values than females for these body conformation traits. The chocolate Sapsarees had greater averages for body weight, body height and chest depth. The older animals (>2 years) had heavier body weight than younger animals. About 54, 69, 97, 39 and 83.3% of the Sapsarees had hairs with yellow color, straight, medium to long, untangled, and longer around eyes, respectively. Also, about 40% brown eye, 43% curly tail, 78% normal jaw, 86% no missing teeth, 90% no dewclaw, and >90% with black nose, pendent ear, tongue without spots were observed. About 95% males were normal in testicles state. The males performed significantly better than the females for majority of the behavioral traits. For nerve stability, affability, wariness, adaptability, sharpness, activity, and reaction during blood drawn about 79%, 73%, 76%, 61%, 70%, 48% and 81% of the Sapsarees performed at desired level. In general, the Sapsarees showed good characteristics for both morphological and behavioral traits, which can be exploited to use the Sapsaree breed as a companion or guide dog.

Implant Fixture Installation in the Anterior Mandible by Use of a Mucosa Supported Surgical Template Based on Computer Assisted Treatment Planning (컴퓨터보조 기반 점막지지 서지컬템프레이트를 이용한 하악전치부 임플란트 식립)

  • Lee, Jee-Ho;Kim, Soung-Min;Kim, Myung-Joo;Park, Jung-Min;Seo, Mi-Hyun;Myoung, Hoon;Lee, Jong-Ho;Kim, Myung-Jin
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.33 no.2
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    • pp.158-165
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    • 2011
  • A 73-year-old Korean female patient with a fully edentulous mandible was planned to have five implant fixtures installed in the anterior mandible for the fixed prosthesis. After 3-dimensional (3D) computed tomographic scanning was transferred to OnDemand3D$^{(R)}$ (Cybermed Co., Seoul, Korea) software program for the virtual planning, five fixtures of MK III Groovy RP implants of Branemark System$^{(R)}$ (Nobel Biocare AB Co., Goteborg, Sweden) were installed in the anterior mandible between both mental foramens using In2Guide$^{(R)}$ (CyberMed Co., Seoul, Korea) mucosa-supported surgical template with Quick Guide Kit$^{(R)}$ (Osstem Implant Co., Seoul, Korea) systems. Fixture installations were completed successfully without any complications, such as mental nerve injury, bony bleedings, fenestrations and other unexpected events. Postoperative computed tomographic scans were aligned and fused to the planned implant, then angular and linear deviations were compared with the planned virtual implants. The mean angular deviation between the planned and actual implant axes was $3.42{\pm}1.336^{\circ}$. The mean distance between the planned and actual implant at the neck area was $0.544{\pm}0.290$ mm horizontally and $0.118{\pm}0.079$ mm vertically. The average distance between the planned and actual implant at the apex area was $1.166{\pm}0.566$ mm horizontally and $0.14{\pm}0.091$ mm vertically. These results could be considered more precise and accurate than previous reports, and even our recent results. The entire procedures of this case are reported and reviewed.

A Study on Improving Pricing Criteria for Post-Construction Evaluation (건설공사 사후평가 용역대가기준 개선방안)

  • Kim, Seok;Lee, Du-Heon;Park, Jae-Woo
    • The Journal of the Korea Contents Association
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    • v.16 no.8
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    • pp.661-670
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    • 2016
  • In 2000, post-construction evaluation was introduced for the purposes to evaluate demand, cost, and construction period of public construction projects and to reduce errors of public order agencies. However, pricing guide of post-construction evaluation has not been established, which becomes a cause of quality degradation of post-construction service and conflict occurrence. This study suggests the pricing guide in the form of percentage of construction cost method and cost plus fee method based on data of post-construction evaluation. This study investigates the construction costs and service costs for post-construction evaluation and conducts the comparative analysis of 'percentage of construction cost method' and 'cost plus fee method.' The analysis result shows 'cost plus fee method' is more accuracy than 'percentage of construction cost method.' In particular, cost plus fee method includes various correction coefficients, such as distance, area, and integration, in order to reflect the project characteristics of each infrastructure, and suggests linear construction (roads, railways), nonlinear construction I (housing and industry complex), and nonlinear construction II (airports, seaports, dams, water and sewage).