상하부 배합을 달리함에 의한 기초 매트 매스콘크리트의 수화열 균열저감

한천구 ( Han Cheon-goo ),김민호 ( Kim Min-ho ) 한국건축시공학회 2017 한국건축시공학회지 Vol.17 No.1

In this research, considering the practical conditions at field, thermal cracking reducing method was suggested based on the comparative analysis between predicted value and actual value obtained from the actual structure member with optimum mix design. The optimum mix design was deduced from the various mix designs with various proportions of cementitious binder for upper and lower placement lifts of mat-foundation mass concrete. Therefore, before field applications, the mix designs were obtained from the theoretical analysis obtained by MIDAS GEN for upper lift was OPC to FA of 85 to 15, and for lower lift was OPC to FA to BS of 50 : 20 : 30. Based on this mix design, the actual concrete for field was determined and all concrete properties were reached within the predicted range. Especially, the temperature properties of mass concrete at core was approximately 39℃ of temperature difference for low-heat mix design, while approximately 54℃ was shown for normal mix design currently used. Additionally, in the case of cracking index, the low heat mix design showed about 1.4 of relatively high value while the normal mix design showed 1.0. Therefore, it can be stated that applying low heat mix design and different heating technique between upper and lower placement lifts for mass concrete are efficient to control the thermal cracking.

Design of Mixed-flow pump for Ns475 Based on Optimum Design Database

김성,이경용,김진혁,윤준용,최영석 한국유체기계학회 2018 International journal of fluid machinery and syste Vol.11 No.2

In this study, a mixed-flow pump with a specified specific speed was optimally designed by utilizing computational fluid dynamics (CFD). Additionally, the shape of the mixed-flow pump and flow characteristics depending on the specific speed were studied, in order to development of hydrodynamic design system for mixed-flow pump. A mixed-flow pump consists of an impeller and a diffuser and the shapes of mixed-flow pumps show a certain tendency depending on specific speed. With an analysis of the shapes of a mixed-flow pump, the optimal shape to satisfy design specifications can easily be designed. The design variables of the impeller and diffuser were defined in meridional plane and vane plane development, and optimum design of the impeller and diffuser was carried out by using design of experiment (DOE). The tendencies of design variables depending on specific speed were analyzed by utilizing the shape of optimally designed mixed-flow pump. The mixed-flow pump shape of required design specification was designed by using the tendencies of design variables depending on specific speed. The performance of designed model has been verified using CFD.

Design of Mixed-flow pump for Ns475 Based on Optimum Design Database

Sung Kim,Kyoung-Yong Lee,Jin-Hyuk Kim,Joon-Yong Yoon,Young-Seok Choi 한국유체기계학회 2018 International journal of fluid machinery and syste Vol.11 No.2

In this study, a mixed-flow pump with a specified specific speed was optimally designed by utilizing computational fluid dynamics (CFD). Additionally, the shape of the mixed-flow pump and flow characteristics depending on the specific speed were studied, in order to development of hydrodynamic design system for mixed-flow pump. A mixed-flow pump consists of an impeller and a diffuser and the shapes of mixed-flow pumps show a certain tendency depending on specific speed. With an analysis of the shapes of a mixed-flow pump, the optimal shape to satisfy design specifications can easily be designed. The design variables of the impeller and diffuser were defined in meridional plane and vane plane development, and optimum design of the impeller and diffuser was carried out by using design of experiment (DOE). The tendencies of design variables depending on specific speed were analyzed by utilizing the shape of optimally designed mixed-flow pump. The mixed-flow pump shape of required design specification was designed by using the tendencies of design variables depending on specific speed. The performance of designed model has been verified using CFD.

현장 콘크리트 타설시 양생온도와 대기시간을 고려한 배합설계 결정

문성우,이성행,최현욱 한국건설관리학회 2019 한국건설관리학회 논문집 Vol.20 No.1

The concrete mix should be designed and produced to reflect the specific site conditions during concrete placement. That is, the concrete mix design should be planned considering temperatures, work environments, pouring methods, etc. The objective of this research is to understand the external factors of curing temperature and delay time that influence concrete strengths during pouring work, and provide concrete mix design that can be most robust to the effects of external factors. The Taguchi’s robust method is used in preparing the concrete mix design to achieve the research objective. In a case study, an indoor concrete test was performed to find the optimal combination of concrete mixes with external factors of curing temperature and delay time. Concrete test cylinders were made to test concrete strengths given different external factors. The study results showed that the optimal performance of concrete strength can be achieved by applying the robust method when preparing ac concrete mix design.

Design optimization for mixed-flow pump impeller by improved suction performance and efficiency with variables of specific speeds

Sung Kim,Yong-In Kim,Jin-Hyuk Kim,Young-Seok Choi 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.6

In this study, the shape of a mixed-flow pump impeller and its flow characteristics as a function of the specific speed are studied to improve its suction performance and efficiency. The shapes of mixed-flow pump impellers show a trend based on the specific speed. To construct the optimum database, a mixed-flow pump impeller with a specified specific speed is optimally designed using computational fluid dynamics (CFD) and design of experiment (DOE). The design variables of the impeller are defined in the meridional plane and vane plane development for impeller. By analyzing the trends of different mixed-flow pump impeller shapes, the optimized shape that satisfies the design specification can be designed easily. The trend exhibited by the design variables depending on the specific speed is analyzed using the shape of the optimally designed mixed-flow pump impeller. The shape of the mixed-flow pump impeller, as per the required design specification, is designed using the trends of the design variables based on the specific speed. The performance of the designed model is verified using CFD and experimental test.

Design Optimization of Mixed-flow Pump in a Fixed Meridional Shape

Kim, Sung,Choi, Young-Seok,Lee, Kyoung-Yong,Kim, Jun-Ho Korean Society for Fluid machinery 2011 International journal of fluid machinery and syste Vol.4 No.1

In this paper, design optimization for mixed-flow pump impellers and diffusers has been studied using a commercial computational fluid dynamics (CFD) code and DOE (design of experiments). We also discussed how to improve the performance of the mixed-flow pump by designing the impeller and diffuser. Geometric design variables were defined by the vane plane development, which indicates the blade-angle distributions and length of the impeller and diffusers. The vane plane development was controlled using the blade-angle in a fixed meridional shape. First, the design optimization of the defined impeller geometric variables was achieved, and then the flow characteristics were analyzed in the point of incidence angle at the diffuser leading edge for the optimized impeller. Next, design optimizations of the defined diffuser shape variables were performed. The importance of the geometric design variables was analyzed using $2^k$ factorial designs, and the design optimization of the geometric variables was determined using the response surface method (RSM). The objective functions were defined as the total head and the total efficiency at the design flow rate. Based on the comparison of CFD results between the optimized pump and base design models, the reason for the performance improvement was discussed.

서비스마케팅믹스의 요소를 활용한 새로운 서비스블루프린트 제안에 관한 연구 -커피전문점 서비스시스템을 중심으로-

한수정,이재환 디자인융복합학회(구.한국인포디자인학회) 2012 디자인융복합연구 Vol.11 No.3

Service's characteristics such as intangibility, simultaneity, heterogeneity and extensiveness make it difficult to design services. For such reason, a systematic development using a tool kit is needed for service design. Service blueprint which is one of representative methodologies of service design, makes it possible to see tangible and intangible components of service design and their interaction at a look. But the current components of blueprint are inadequate to cover all service system elements, so lots of service design firms are using their own service blueprints. Service blueprint is a methodology used for collecting results from various observations, examinations and analyses to design services like brainstorming. As a similar concept, service marketing mix 7P in the marketing field which classifies service components into seven categories, has an inherent purpose that is similar to service blueprint in the way that it is to establish strategies through the interaction among service components. On the assumption that a new service marketing mix which is applied to service marketing mix 7P(Product, Price, Place, Promotion, People, Physical Evidence and Process) that are more subdivided than service blueprint's components, is able to contain more comprehensive services, this study proposed a new service 7P blueprint. 서비스(Service)가 가지고 있는 무형성, 동시성, 이질성, 소멸성 등의 특성은 서비스를 디자인하는데 어려움을 준다. 때문에 서비스디자인(Service design)시 방법론(Tool kit)을 활용한 체계적인 개발을 필요로 한다. 서비스디자인의 대표적인 방법론 중 하나인 서비스블루프린트(Service blueprint)는 유, 무형의 서비스디자인의 구성요소들과 그 상호작용을 한 눈에 볼 수 있다는 목적과 장점을 가지고 있다. 하지만 현 블루프린트의 구성요소들은 서비스시스템의 요소들을 모두 아우르는데 부족함이 있어 많은 서비스디자인 전문회사들은 그들만의 응용된 서비스블루프린트를 사용하고 있다. 서비스블루프린트는 서비스를 디자인하기 위해 브레인스토밍 하듯 다양한 관찰, 조사, 분석한 내용들을 하나로 수렴하는 단계에서 사용하는 방법론이다. 유사한 개념으로 마케팅 분야에서 서비스마케팅믹스(Service Marketing Mix) 7P는 서비스의 구성요소들을 7개의 카테고리로 분류한 것으로, 포지셔닝을 위해 7개로 정리된 서비스의 구성요소의 상호작용을 살펴 전략을 세운다는 점에서 서비스블루프린트의 존재이유와 유사한 태생적인 목적을 가지고 있다. 본 연구에서는 서비스블루프린트 구성요소보다 좀 더 세분화된 서비스 마케팅믹스 7P(Product, Price, Place, Promotion, People, Physical Evidence, Process)를 서비스블루프린트의 구성요소에 접목한 새로운 서비스 마케팅믹스가 더 포괄적인 서비스의 내용을 담을 수 있을 것이라는 가설아래 새로운 서비스7P블루프린트를 제안하고자 한다.

High performance hydraulic design techniques of mixed-flow pump impeller and diffuser

김성,이경영,김준형,김진혁,정욱희,최영석 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.1

In this paper, we describe a numerical study about the performance improvement of a mixed-flow pump by optimizing the design ofthe impeller and diffuser using a commercial computational fluid dynamics (CFD) code and design-of-experiments (DOE). The designvariables of impeller and diffuser in the vane plane development were defined with a fixed meridional plane. The design variables weredefined by the vane plane development, which indicates the blade-angle distributions and length of the impeller and diffuser. The vaneplane development was controlled using the blade-angle in a fixed meridional plane. The blade shape of the impeller and diffuser weredesigned using a traditional method in which the inlet and exit angles are connected smoothly. First, the impeller optimum design wasperformed with impeller design variables. The diffuser optimum design was performed with diffuser design variables while the optimallydesigned impeller shape was fixed. The importance of the impeller and diffuser design variables was analyzed using 2k factorial designs,and the design optimization of the impeller and diffuser design variables was determined using the response surface method (RSM). Theobjective functions were defined as the total head (Ht) and the total efficiency (ηt) at the design flow rate. The optimally designed modelwas verified using numerical analysis, and the numerical analysis results for both the optimum model and the reference model were comparedto determine the reasons for the improved pump performance. A pump performance test was carried out for the optimum model,and its reliability was proved by a comparative analysis of the results of the numerical analysis and an experiment using the optimummodel.

콘크리트의 배합설계에 있어서 신경망의 이용

오주원,이종원,이인원 한국콘크리트학회 1997 콘크리트학회지 Vol.9 No.2

In concrete mix design we need the informations of the codes, the specifications, and the experiences of experts. However we can't consider all factors regarding concrete mix design. The final acceptance depends on concrete quality control test results. In this process we meet the uncertainties of materials. temperature, site environmental situations, personal skillfulness. and errors in calculations and testing process. Then the mix design adjustments must be made. Concrete mix design and adjustments arc somewhat complicated, time-consuming. and uncertain tasks. In this paper, as a tool to minimize the uncertainties and errors the neural network is applied to the concrete mix design. Input data to train and test the neural network are obtained numerically from the results of design following the concrete standard specifications of Korea. The 28-days compressive strengths which are variate according to the uncertainties and errors are considered. The results show that neural networks have a strong potential as a tool for concrete mix design. 콘크리트의 배합설계를 위해서는 각종 콘크리트 표준 시방서의 내용에 대하여 잘 알아야 할 뿐 아니라 현장 경험이 많은 전문가의 경험을 필요로 한다. 그러나 배합 설계에 관련된 모든 인자들과 그 인자들 간의 상호작용에 대하여 모두 고려할 수는 없다. 따라서 적적한 배합설계에 관한 판단은 품질관리를 위한 재료시험을 통하여 판단할 수밖에 없고 그 결과에 따라 보정하는 과정을 거치게 된다. 이렇듯 콘크리트의 배합설계는 재료, 온도, 현장조건, 기술자의 숙련도 등에 대하여는 불확실성이 존재하고 계산과 시험과정에 존재하는 오차로 인하여 엄격한 품질관리를 하여야만 하기 때문에 자칫 지루하며 복잡하고 힘든 일이 될 수밖에 없다. 본 연구에서는 이렇듯 콘크리트의 배합설계 과정에서 나타나는 피할 수 없는 불확실성과 오차들을 최소화하기 위하여 신경망을 적용하였다. 신경망의 학습과 검증을 위한 자료는 콘크리트 표준시방서에 따라 설계기준 강도, 굵은골재 최대치수, 슬럼프, 골재의 조립율 등을 변화시켜 가면서 이론적으로 물-시멘트비, 잔골재율, 단위 수량, 단위 시멘트량, 단위 잔골재량, 단위 굵은 골재량 등을 구하여 사용하였다. 특히 콘크리트의 실제강도는 동일한 조건하에서 강도시험을 실시하여도 결과가 서로 다르게 나타나는 확율변수인점도 고려하였다. 콘크리트의 배합설계에 신경망을 적용한 결과는 그 적용성이 매우 컸다.

실내디자인에서 'Mix & Match'의 속성 및 표현특성에 관한 연구

조성희(Cho, Sung-Heui),최인영(Choi, In-Young) 한국실내디자인학회 2010 한국실내디자인학회논문집 Vol.19 No.1

This study examines attributes and expression characteristics of ‘Mix & Match’ which is one of the major current rends in interior design. The concept and background of ‘Mix & Match’ was ascertained through research of previous documents and studies, and its attributes were explored. In order to examine the expression characteristics to see how they are expressed in actual interior designs, case analyses were carried out centering on the expression elements such as material, light & lighting, color, fumiture and objects which were regarded as important in previous studies and related articles so far. The case analyses were carried out for works where the concept of ‘Mix & Match’ was prominent in designs produced in 2007 and 2008, chosen form the main reports of the representative interior design journals, ‘Interiors’ and ‘INTERNI & Decor’. As a result, it has been found that ‘Mix & Match’ is not Limited to one attribute but the temporal, spatial and genre attributes are present all at the same time, or various expression elements exist in one attribute. This is a distinct character commonly shown in most of the cases and each expression element is expressed in variety according to spatial concept, from a simple parallel to substitution, transfer and modification (simplification, transformation of the scale, rate modification etc.) Therefore, in creating the space for ‘Mix & Match’ or in interpretation of it, the understanding of these expression characteristics would make it possible for clearer and more various applications of design, and futhermore will be meaningful for supply and accumulation of reference in design communication.