• Title/Summary/Keyword: vacuum cleaner

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Components Clustering for Modular Product Design Using Network Flow Model (네트워크 흐름 모델을 활용한 모듈러 제품 설계를 위한 컴포넌트 군집화)

  • Son, Jiyang;Yoo, Jaewook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.7
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    • pp.263-272
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    • 2016
  • Modular product design has contributed to flexible product modification and development, production lead time reduction, and increasing product diversity. Modular product design aims to develop a product architecture that is composed of detachable modules. These modules are constructed by maximizing the similarity of components based on physical and functional interaction analysis among components. Accordingly, a systematic procedure for clustering the components, which is a main activity in modular product design, is proposed in this paper. The first phase in this procedure is to build a component-to-component correlation matrix by analyzing physical and functional interaction relations among the components. In the second phase, network flow modeling is applied to find clusters of components, maximizing their correlations. In the last phase, a network flow model formulated with linear programming is solved to find the clusters and to make them modular. Finally, the proposed procedure in this research and its application are illustrated with an example of modularization for a vacuum cleaner.

The Public Choice Analysis of Korean Mobile Telecom Policy (이동통신정책의 공공선택 분석)

  • Shin, Jin
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.3
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    • pp.493-499
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    • 2015
  • In Korea mobile phone subscribers exceeded 1 million people in 1995, and ten million people in 1998. Prevalence of the mobile phone increased dramatically over 110% compared to the population. Almost every family members including children uses more than one mobile terminal. Mobile phone is obviously more necessary good than washer, vacuum cleaner and passenger car. Our daily life are conveniently positioned with mobile communication, but communication related costs including the price of the device and service charges become a big burden on the household. But the government does not seem to do the right role at the right time to prevent the market failure to maximize consumer welfare and social welfare through supporting fair competition. This principal-agent problem issues of mobile communication policies will be understood in perspective of public choice against joint use of the mobile communication network, number portability, separation of phone distribution and phone service, network neutrality, mobile phone subsidy since the early 1990s when mobile phone service was introduced in Korea.

Application of Airfoil Impeller for Enhancement of Aerodynamic Performance of High Speed Centrifugal Fan (고속 원심홴의 공력성능 향상을 위한 에어포일 임펠러 적용)

  • Park, Kyung Hyun;Park, Chang Hwan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.5
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    • pp.321-327
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    • 2016
  • This paper presents the application of airfoil impeller for enhancement of aerodynamic performance of a high speed centrifugal fan. Three airfoil impellers are proposed, considering the maximum thickness and the location of maximum thickness of the airfoil. C4 airfoil thickness distribution is applied to the three airfoil impellers. The impellers are evaluated using CFD (computational fluid dynamics) and suction power test. From the results, it is confirmed that flow separations on the pressure side of the impeller blades and the pressure side of diffuser blades are reduced when airfoil blade is applied to the impellers. It is also confirmed that with the centrifugal fan having airfoil impellers, there is an increase in fan efficiency by approximately 3% and reduction in specific sound level by approximately 1.3 dB(A).

Perceptual Evaluation of Noise Sources in a Chamber for Residential and Working Environment (주거 및 사무환경 챔버에서의 생활소음에 대한 감성적 평가)

  • Jeon, Jin-Yong;Kim, Kyong-Ho;Jung, Jeong-Ho;Ryu, Jong-Kwan;Cho, Moon-Jae
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.6
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    • pp.437-444
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    • 2002
  • This paper is to provide the basic way of a acoustical evaluation and efficient control noise by investigating the limits of perceptual loudness of living environment and by finding out any correlation between Physical characteristics of noise and psychoacoustic parameters. The limits of perceptual loudness were selected by the subjects in a chamber for residential and working environment. And the noise sources were analyzed to find out whether there is any correlation with Zwicker parameters and ACF factors. In this study especially, to set up the domestic evaluation grade about floor impact noise. we'd like to suggest the loudness Perception research result as fundamental resource for setting up the evaluation grade through the result that is based on annoyance. In the result of this research, upper limit of heavy-weight impact noise was L-60, and lower limit of it was L-50. On the other hand, upper limit of light-weight impact noise was L-70, and lower limit of it was L-55. It seemed that the loudness of noise from vacuum cleaner noise does not affect its perceived noisiness. Noises implicated In human such as floor walking noise and talking sound, are the most irritating noise in office environment.

A Case Study of Introduction to Engineering Design Course using LEGO MINDSTORM NXT (LEGO MINDSTORM NXT를 이용한 공학설계입문 운영사례)

  • Yi, Kang
    • Journal of Engineering Education Research
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    • v.12 no.2
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    • pp.83-88
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    • 2009
  • In this paper the author proposes a case study of a freshmen introduction to engineering design course ing LEGO Mindstorm NXT and analyzes the survey results of the course. The diffilculties are that this course should provide various aspects of design experiences to the students while not requiring the major knowledge and skills and it should attract the students to the engineering major. According to our case study LEGO mindstorm can be a good solution to this problem. The design experience with LEGO Mindstorm NXT provides students with various aspects of design experiences including defining problem, finding constraints and functions, exploring design space, and performing preliminary design, as well as fun. This paper also provides a project list that can be used for freshmen design experience including soccer game robots, line tracer, and vacuum cleaner etc.

A Study on Physical Characteristics and Plastics Recycling of Used Small Household Appliances (폐소형가전의 물리적 성상 분석 및 플라스틱 재활용에 관한 연구)

  • Choi, Woo Zin;Park, Eun Kyu;Kang, Seok Hwan;Jung, Bam Bit;Kim, Soo Kyung
    • Resources Recycling
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    • v.25 no.1
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    • pp.31-39
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    • 2016
  • Small household appliances such as electric rice cooker, a vacuum cleaner, an electric fan, etc. are diverse and complex due to the materials and components and waste streams from the manufacturing processes. In the present study, physical characterization of small e-wastes was analyzed on major items including electric rice cooker after manual dismantling. Small household appliances is an important potential source of waste plastic, however, recycling plastics from small e-waste is still unusual. The present communication gives results of separation processes on black plastics and the limitations of these sorting processes in used small household appliances.

The Public Choice Analysis of Korean Mobile Telecom Policy (이동통신 정책의 공공 선택 분석)

  • Shin, Jin;Park, Dea-Woo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2014.10a
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    • pp.917-920
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    • 2014
  • In Korea mobile phone subscribers exceeded 1 million people in 1995, and ten million people in 1998. Prevalence of the mobile phone increased dramatically over 110% compared to the population. And all family members including children and students use one or two mobile terminal. Mobile phone is obviously necessary good more than washer, vacuum cleaner, passenger car. Our daily life with mobile communication are conveniently positioned, but communication related costs including the price of the device has become a big burden on the household. But the government does not seem to do the right role at the right time to prevent the failure of the market to further maximize consumer welfare and social welfare through fair competition. This principal-agent problems exist especially in perspective of joint use of the mobile communication network, number portability, separation of phone distribution and phone service and network neutrality among in mobile communication policies since the early 1990s up to now.

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Simultaneous Transfer and Patterning of CVD-Grown Graphene with No Polymeric Residues by Using a Metal Etch Mask

  • Jang, Mi;Jeong, Jin-Hyeok;Trung, T.Q.;Lee, Nae-Eung
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.642-642
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    • 2013
  • Graphene, two dimensional single layer of carbon atoms, has tremendous attention due to its superior property such as high electron mobility, high thermal conductivity and optical transparency. Especially, chemical vapor deposition (CVD) grown graphene has been used as a promising material for high quality and large-scale graphene film. Unfortunately, although CVD-grown graphene has strong advantages, application of the CVD-grown graphene is limited due to ineffective transfer process that delivers the graphene onto a desired substrate by using polymer support layer such as PMMA(polymethyl methacrylate). The transferred CVD-grown graphene has serious drawback due to remaining polymeric residues generated during transfer process, which induces the poor physical and electrical characteristics by a p-doping effect and impurity scattering. To solve such issue incurred during polymer transfer process of CVD-grown graphene, various approaches including thermal annealing, chemical cleaning, mechanical cleaning have been tried but were not successful in getting rid of polymeric residues. On the other hand, lithographical patterning of graphene is an essential step in any form of microelectronic processing and most of conventional lithographic techniques employ photoresist for the definition of graphene patterns on substrates. But, application of photoresist is undesirable because of the presence of residual polymers that contaminate the graphene surface consistent with the effects generated during transfer process. Therefore, in order to fully utilize the excellent properties of CVD-grown graphene, new approach of transfer and patterning techniques which can avoid polymeric residue problem needs to be developed. In this work, we carried out transfer and patterning process simultaneously with no polymeric residue by using a metal etch mask. The patterned thin gold layer was deposited on CVD-grown graphene instead of photoresists in order to make much cleaner and smoother surface and then transferred onto a desired substrate with PMMA, which does not directly contact with graphene surface. We compare the surface properties and patterning morphology of graphene by scanning electron microscopy (SEM), atomic force microscopy(AFM) and Raman spectroscopy. Comparison with the effect of residual polymer and metal on performance of graphene FET will be discussed.

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Exposure Assessment of Dust, Ultra Fine Dust(Particulate Matter 2.5, PM2.5) and Black Carbon among Aircraft Cabin Cleaners (항공기 기내 청소노동자의 분진, 초미세먼지(PM2.5) 및 블랙카본 노출수준 평가)

  • Hyunhee Park;Sedong Kim;Sungho Kim;Seung-Hyun Park
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.33 no.2
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    • pp.171-187
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    • 2023
  • Objectives: Aircraft cabin cleaning work is characterized by being performed within a limited time in a narrow and enclosed space. The objective of this study was to evaluate the exposure levels to dust, ultra fine dust(PM2.5) and black carbon(BC) among aircraft cabin cleaners. Methods: Active personal air sampling for respirable dust(n=73) and BC(n=47) was conducted during quick transit cleaning(cabin general and vacuum-specific) and seat cover replacement and total dust and PM2.5 were area-air-sampled as well. Also, size distribution of particle was identified with the cleaning workers targeted. Dusts were collected with PVC filters using gravimetric analysis. The concentration of PM2.5 and the particle size distribution were measured with real-time direct reading portable equipment using light scattering analysis. The concentration of BC was measured by aethalometer(filter-based real-time light absorption analysis instrument). Results: The geometric mean of respirable dust was the highest at vacuum cleaning as 74.4 ㎍/m3, following by replacing seat covers as 49.3 ㎍/m3 and cabin general cleaning as 47.8 ㎍/m3 . The arithmetic mean of PM2.5 was 4.83 ~ 9.89 ㎍/m3 inside the cabin, and 28.5~44.5 ㎍/m3 outside the cabin(from bus and outdoor waiting space). From size distribution, PM2.5/PM10 ratio was 0.54 at quick transit cleaning and 0.41 at replacing seat covers. The average concentration of BC was 2~7 ㎍/m3, showing a high correlation with the PM2.5 concentration. Conclusions: The hazards concentration levels of aircraft cabin cleaners were very similar to those of roadside outdoor workers. As the main source of pollution is estimated to be diesel vehicles operating at airports, and it is necessary to replace older vehicles, strengthen pollutant emission control regulations, and introduce electric vehicles. In addition, it is necessary to provide as part of airport-inftastructure a stable standby waiting space for aircraft cabin cleaners and introduce a systematic safety and health management system for all workers in the aviation industry.

The Study and Conservation of Woven Cigarette Inserts (담배 사은품 실크 인서트(Silk Inserts)에 관한 연구와 보존처리)

  • Lee, Young-Joo
    • Journal of the Korean Society of Clothing and Textiles
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    • v.30 no.3 s.151
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    • pp.447-457
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    • 2006
  • The purpose of this study is to document and preserve an unidentified textile purchased at a flea market. This study object is important because it is one of the very rare silk insert series from 1930s which were created for commercial use(as inclusion in cigarette packages). The investigation was conducted by researching the limited publications that discuss silk inserts, visiting many sites on the internet that offer such inserts for sale or catering to the collectors of these silk inserts, and especially visiting the collection of silk inserts, named the J.R. Burdick Collection, at the Metropolitan Museum of Art, New York. Several pieces matched the patches used in the study piece. But Buidick's description on time frame(1912-1915) did not indicate the full range of production of silk inserts. After the identification of object, the conservation treatment was carefully done using adhesives. The results of this study can be summarized as follows; 1. The silk inserts of the study object were included as promotions by some company owned by the American Tobacco Company, probably at some time between 1934 and 1939. 2. The initial stage in the conservation treatment was mechanical surface cleaning using a vacuum cleaner. After vacuuming, humidification was conducted to reduce creases in the top of the object. The damaged areas were backed with stabiltax coated with a solution of Elvace 45675 since the fiber of this object was too deteriorated. 3. Adhesive treatments using Elvace showed satisfactory results: flexibility, strength, no damaging effects on the study object, removability without damaging the object.