• Title, Summary, Keyword: sizing

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Optimal Design of Generalized Process-storage Network Applicable To Polymer Processes (고분자 공정에 적용할 수 있는 일반화된 공정-저장조 망구조 최적설계)

  • Yi, Gyeongbeom;Lee, Euy-Soo
    • Korean Chemical Engineering Research
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    • v.45 no.3
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    • pp.249-257
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    • 2007
  • The periodic square wave (PSW) model was successfully applied to the optimal design of a batch-storage network. The network structure can cover any type of batch production, distribution and inventory system, including recycle streams. Here we extend the coverage of the PSW model to multitasking semi-continuous processes as well as pure continuous and batch processes. In previous solutions obtained using the PSW model, the feedstock composition and product yield were treated as known constants. This constraint is relaxed in the present work, which treats the feedstock composition and product yield as free variables to be optimized. This modification makes it possible to deal with the pooling problem commonly encountered in oil refinery processes. Despite the greater complexity that arises when the feedstock composition and product yield are free variables, the PSW model still gives analytic lot sizing equations. The ability of the proposed method to determine the optimal plant design is demonstrated through the example of a high density polyethylene (HDPE) plant. Based on the analytical optimality results, we propose a practical process optimality measure that can be used for any kind of process. This measure facilitates direct comparison of the performance of multiple processes, and hence is a useful tool for diagnosing the status of process systems. The result that the cost of a process is proportional to the square root of average flow rate is similar to the well-known six-tenths factor rule in plant design.

Intercomparisonn of Techniques for Pressure Tube Inspection of Pressurized heavy Water Reactor (가압 중수로형 원자력발전소 압력관 비파괴검사기술의 상호비교)

  • Lee, Hee-Jong;Kim, Yong-Si;Yoon, Byung-Sik;Lee, Young-Ho
    • Journal of the Korean Society for Nondestructive Testing
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    • v.25 no.4
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    • pp.294-303
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    • 2005
  • This paper describes the analysis results of a series f Round-Robin test that was performed to intercompare inspection and diagnosis techniques for characterization of pressure tube f a pressurized heavy water reactor under the Coordinated Research Project(CRP) of IAEA's nuclear Power Programme. For this test, six nations, Korea, Canada, India, Argentina, Rumania, and China that currently have pressurized heavy water reactors under operation involved, and the "KOR-1" pressure tube sample prepared by Korea was used. Two kinds of NDE technique, ultrasonic and eddy current test, were applied for these tests. The "KOR-1" pressure tube sample contains total 12 artificial flaws such as crack-like EDM notches, wear that is similar to the real flaws and can be produced on the pressure tubes during plant operation. Test results showed that seven laboratories from six nations detected all twelve flaws in "KOR-1" specimen by using ultrasonic and eddy current test methods, and ultrasonic test method was more accurate than eddy current test method in flaw detectin and sizing. ID flaws in pressure tube sample were more easily detected and accurately sized than OD flaws.

Nondestructive Examination of Ferromagnetic Tube Using Magnetic Saturation Eddy Current Technique (자기포화 와전류기법에 의한 자성 튜브 비파괴검사)

  • Lee, Hee-Jong;Cho, Chan-Hee;Song, Seok-Yoon;Jee, Dong-Hyun;Jung, Jee-Hong
    • Journal of the Korean Society for Nondestructive Testing
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    • v.28 no.5
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    • pp.407-415
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    • 2008
  • The tubes in heat exchanger are typically made from copper alloy, stainless steel, carbon steel, titanium alloy material. type-439 ferritic stainless steel is ferromagnetic material, and furnish higher heat transfer rates than austenitic stainless steels and higher resistance to corrosion-induced flaws. Ferritic stainless steel can typically be found in low-pressure(LP) feedwater heaters and moisture separator reheaters(MSRs). LP feedwater heaters generally utilize thin wall type-439 stainless steel tubing, whereas MSRs typically employ a heavier wall tubing with integral fins. Service-induced damage can occur on the OD(outside diameter) surface of type-439 ferritic stainless steel tubing which is employed for MSRs tubing, and the most typical damage mechanism is vibration-induced tube-to-TSP(tube support plate) wear and fatigue cracking. The wear has been reported that occurs mainly on the OD surface. Accordingly, in this study, we have evaluated the flaw sizing capability of magnetic saturation eddy current technique using magnetic saturation probe and flawed specimen.

Effect of Nanocellulose and Aminated Starch on Tensile and Thermal Properties of Plasticized Starch Film (가소화 전분필름의 강도 및 열적 성질에 미치는 나노셀룰로오스 및 아민화전분의 첨가영향)

  • Kim, Bo-Yeon;Han, Song-Yi;Lee, Sung-Yong;Kim, Young-Kyoon;Kim, Nam-Hun;Lee, Seung-Hwan
    • Journal of the Korean Wood Science and Technology
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    • v.42 no.4
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    • pp.376-384
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    • 2014
  • This study investigated the effect of nanocellulose, such as microfibrillated cellulose (MFC) and cellulose nanocrystal (CNC), and aminated starch on tensile property and thermal stability of plasticized starch film. Glycerol (23 wt%) was used as a plasticizer and nanocelluloses of 1-30 parts per hundred parts of resin (phr) in the basis of plasticized starch were added. Tensile strength and elastic modulus increased with increasing nanocellulose addition amount, whereas elongation at break decreased. Tensile properties of MFC-reinforced starch film were higher than those of CNC-reinforced film. Optimum addition amount of aminated starch, which is commonly used for paper sizing, to improve tensile property of film, was found to be 5%. And 1% addition of aminated starch showed the best effect in the improvement of tensile property of the film. Thermal stability was improved with the addition of MFC to plasticized starch film with and without aminated starch.

Analysis of Broken Rice Separation Efficiency of a Laboratory Indented Cylinder Separator

  • Kim, Myoung Ho;Park, Seung Je
    • Journal of Biosystems Engineering
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    • v.38 no.2
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    • pp.95-102
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    • 2013
  • Purpose: Using a laboratory indented cylinder separator, broken rice separation experiments were conducted and the characteristics of the separation process were studied to provide information for developing a prototype indented cylinder broken rice separator. Methods: Rice (Ilmi variety) milled in a local RPC was used for the experiment. Rice kernels were classified into four groups according to their length l; whole kernels (I > 3.75 mm), semi-whole kernels (2.5 < I < 3.75 mm), broken kernels (1.75 < I < 2.5 mm), and foreign matters (I < 1.75 mm). A laboratory grain cleaner, Labofix '90 (Schmidt AG, Germany) was used for the experiments. Experiments were designed as a $4{\times}4$ factorial arrangement in randomized blocks with three replications. Cylinder rotational speeds (17, 34, 51, 68 rpm) and trough angles (15, 37.5, 60, $82.5^{\circ}$) were the two factors and feed rates (25, 50 kg/h), indent shapes (Us, $S_1$ type), and indent sizes (2.5, 3.75 mm) were treated as the blocks. Two 125 g samples and one 125 g sample were taken at the cylinder outlet and from the trough, respectively. The whole, semi-whole, and broken kernel weight ratio of the samples and feed was determined by a rice sizing device. From these weight ratios, purities, degrees of extraction and coefficient of separation efficiency were calculated. Results: Trough angle, cylinder speed, and their interaction on the coefficient of separation efficiency were statistically significant. Cylinder speed of 17, 34, and 51 rpm made the most effective separation when the trough angle was $15^{\circ}$ or $37.5^{\circ}$, $60^{\circ}$, and $82.5^{\circ}$, respectively. Maximum values of coefficient of separation efficiency were in the range of 60 to 70% except when the indent size was 2.5 mm and were recorded for the combinations of low cylinder speed (17 rpm) with medium trough angle ($37.5^{\circ}$ or $60^{\circ}$). Indent shape did not appear to make any noticeable difference in separation efficiency. Conclusions: Due to the interaction effect, the trough angle needs to be increased appropriately when an increase in cylinder speed is made if a rapid drop of effectiveness of separation should be avoided. In commercial applications, $S_1$ type indents are preferred because of their better manufacturability and easier maintenance. For successful separation of broken kernels, the indent size should be set slightly bigger than the actual sizes of broken kernels: an indent size of 3.0 mm for separating broken kernels shorter than 2.5 mm.

The Effects of the Anode Size and Position on the Limiting Currents of Natural Convection Mass Transfer Experiments in a Vertical Pipe (수직 원형관내 자연대류 물질전달실험에서 양극의 면적과 위치가 한계전류에 미치는 영향)

  • Kang, Kyoung-Uk;Chung, Bum-Jin
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.1
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    • pp.1-8
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    • 2010
  • Natural convection heat transfer rates in a vertical pipe were measured for $Gr_H$ number from 2.1x$10^6$ to 1.2x$10^9$. Using the analogy concept, heat transfer experiments were replaced by mass transfer experiments. A cupric acid - copper sulfate ($H_2SO_4-CuSO_4$) electroplating system was adopted as the mass transfer system and the mass transfer rates were measured. Comparison of the results with the existing laminar and turbulent natural convection heat transfer correlations on a vertical plate showed very good agreements except for the high $Gr_H$ case, where the boundary layer inside the vertical pipe interferes. The agreements showed the usefulness of the analogy experiment method. Using 3 different anode size and 6 different geometrical configurations, the effects of the anode size and position were explored. As expected, the anode size and position do not affect the limiting currents for most cases. These results will be used as the experimental background for the positioning and sizing of the anodes for a more complex experiment.

A Study on the Wearing Condition and Satisfaction of Pesticide Protective Clothing (농약방제복 착용실태 및 만족도에 관한 연구)

  • Oh, Young-Soon;Lee, Kyung-Suk;Chae, Hye-Seon;Kim, Kyung-Ran;Kim, Sung-Woo
    • Journal of the Korea Fashion and Costume Design Association
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    • v.16 no.4
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    • pp.217-228
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    • 2014
  • The purpose of this study is to grasp inconveniences and improvements by examining wearing condition and satisfaction of protective clothing targeting 114 Korean farmers and to suggest basic data for enhancement of pattern and wearing satisfaction of protective clothing by understanding problems of pesticide-proof clothing through comparative analysis on the size of its commercial products. Most of male subjects were in charge of spraying pesticide, whereas female were most likely to play an assistant role to hold the hose of pesticide applicator. Both of female and male subjects were very aware of the harmful effect of pesticide on human body and tried to take off the clothes immediately after spraying it to reduce possible damage caused by pesticide. As a result of examining wearing condition, the farmers avoided wearing protective clothing because that it feels hot, stuffy, and uncomfortable to move. This hesitant response of wearing the clothing was not shown significantly in case of female subjects who play an assistant role for spraying. Although the farmers wore protective equipments such as mask or gloves in a proper way as compared to protective clothing, they seemed to choose alternative way rather than best way to block pesticide completely. The satisfaction regarding to the fitting of protective clothing which the subjects showed low in all items of upper-lower clothes except waistline. It is necessary to improve the functionality such as relief from heat stress and convenience for movement rather than design or economic in protective clothing development. As a result of comparing the size of five kinds of commercial protective clothing, the farmers got confused to choose the product since designation method of size across companies showed a significant difference in an identical clothing size. In addition, the sizing system developed on a basis of a well-built man has become a hindering factor in wearing satisfaction of female farmers.

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Research on Actual Usage and Satisfaction of ROKAF Fighter Pilot's Flight Duty Uniform (공군 전투조종사 비행복 착용특성 및 만족도 조사)

  • Lee, Ah Lam;Nam, Yun Ja;Hong, Yu Hwa;Im, Sojung;Lim, Chae Keun
    • Journal of the Korean Society of Clothing and Textiles
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    • v.40 no.4
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    • pp.669-684
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    • 2016
  • This study investigates Korean fighter pilot's usage and satisfaction of a flight duty uniform (FDU). The survey was conducted from October 2014 to March 2015 using Focus Group Interview (FGI) and questionnaires. FGI collected qualitative data about duty and requirements; subsequently, surveys were performed to collect quantitative data about wearing conditions and satisfaction with FDU. The results of the FGI and the questionnaire were as follows. Type of pilot duty was divided into two parts, flight duty and ground duty. It is important to consider duties as well as factors related to survival when developing FDU. According to anthropometric data and wearing size, the basic size for apparel grading should be changed from actual size, 'M95XL' to 'M100L'. It is also necessary to improve the whole sizing system. Further studies about body form changes in pilot's movement are needed to improve mobility because the respondents perceived some restrictions at several body parts in movement with the coverall uniform. Summer FDU had a low satisfaction level in vent hole function and appearance. Furthermore, protection problems in the vent hole were also an issue. Making a seasonal classification of FDU fabric will be more effective than a vent hole to increase a pilot's thermal satisfaction. Respondents had a passive stance towards FDU reform (including pocket change); therefore, a new FDU design strategy should concentrate on improving current FDU functions like mobility (or comfort) rather than dramatic changes. Pilots complained about the quality stability of FDU; therefore, quality control by military administration as well as concrete and clear design instructions by the developer should be attained together. The results obtained in this study are expected to be used as an important basis for the further development of FDU.

Efficient Information System Sizing Selection Using Cloud Computing Platform (클라우드 컴퓨팅 플랫폼을 이용한 효율적인 정보시스템 용량 산정 방법에 관한 연구)

  • Seong, Baek-min;Lee, Min-gyu;Sohn, Hyo-jung;Kim, Jong-bae
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.79-81
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    • 2014
  • Recently, It is built various information systems evolve IT skills. But When you build the information system, Difficult to determine whether the appropriate scale and problems that rely heavily on SI companies and professionals. To solve this problem, Korea Information Security Agency, etc., based on the primary objective was to develop H/W Capacity Equation formally to each system type. But the problems are to present H/W capacity equation by discussion of the expert group of suppliers and relatively long that it is difficult to formally apply in the situation now so it is no longer the limit. In this study, we proposes proper capacity planning techniques, which can guarantee the best performance compared to the budget invested. For this purpose, we derived the proper H/W capacity equation by regression analysis to gather performance metrics and cost of various cases by simulation of a virtual environment in the cloud. Through this study, when capacity planning, It is possible to reduce costs that It is possible to build an information system based on the digitized data and build information system in an environment that does not rely on the SI business or professional.

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A Study of the Proper Sizing of a Subway Station Waiting Area (도시철도 대기공간의 적정규모 산정에 관한 연구)

  • Kim, Jonghwang;Baek, Sungjoon;Nam, Doohee
    • Journal of the Korean Society for Railway
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    • v.19 no.2
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    • pp.262-269
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    • 2016
  • Subway station scales are determined by peak predictions. In this study, the purpose behind the installation of a subway is public transportation convenience and public interest, but economic validity is also important. By proving that the scale of the station is excessive with regard to the target station size for Seoul subway Line 5-8, a reasonable plan. can be sought. According to station installation standards, the area of the station under investigation here is out of the service levels by six stages (A~F), and it must be four or more levels (D). The Actual level for the B level is a two-step design. The Actual ratio for over- Peak predictions is only 17.8% on average. The results of measurements of the excess area and determination of the excessive costs were analyzed by subdividing the area and by calculating it based on the B level, finding that it is possible to provide benefits for customers only in the current design, with an area ratio of 16.3%. Given the weight, it was estimated that current conditions can meet the needs of only 18.6% of the current area. Simplifying the scale calculation method of the station, it is convenient, safe, and advantageous to move citizens only if the scale can be streamlined. Then, with a reduced initial investment, maintenance costs during the operation can be reduced.