• Title/Summary/Keyword: Experimental verification

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A Geothermal Model of Pit Area Using Computational Fluid Dynamics (CFD를 이용한 피트의 지중열 모델 구축에 관한 연구)

  • Min, Joon Ki;Kim, Jeong Tai
    • KIEAE Journal
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    • v.8 no.5
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    • pp.11-16
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    • 2008
  • This research has established CFD model on pit's cool-tube system through heat and air movement simulations, of which data was based on experimental and verification. This research work verified the effectiveness of the cool-tube system by analysing temperature, humidity and air current of the actually installed case. Also, we analysed heat transfer through air current simulation and the results are as followings. Firstly, we experiment on temperature, humidity and speed of air currents of the cool tube system with pit space during the month of May (spring). The average exterior temperature was $16.1^{\circ}C$, and $18.2^{\circ}C$ for the pit, $24.7^{\circ}C$ for the compressor room. Secondly, based on measured data of real case, we have analysed heat transfer through air current simulation and verified our proposed model. The actual measurement of average temperature of exhaust air of the pit's area is $19.7^{\circ}C$ with tolerance of $-0.33^{\circ}C{\sim}-0.6^{\circ}C$ compared to above simulations. Thirdly, having verified air current simulation model with formation of 260,000 and 1,000,000 cells, we could get reasonable near values with 260,000 cells. Lastly, the next step of research would be focused on proposing the best possible pit's cool-tube system after analysis of heat transfer of the air current simulation based on verified CFD model.

Optimization of Two-stage Pretreatment from Soybean Hull for Efficient Glucose Recovery

  • Jung, Ji-Young;Choi, Myung-Suk;Yang, Jae-Kyung
    • Journal of the Korean Wood Science and Technology
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    • v.40 no.2
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    • pp.78-90
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    • 2012
  • Soybean hull is an attractive feedstock for glucose production. To increase the glucose conversion in acid hydrolysis, a pretreatment method combined steam explosion with alkali pretreatment for soybean hull was studied. For first step pretreatment, steam explosion conditions (log Ro 2.45) were optimized to obtain maximum solid recovery and cellulose content. In the second step pretreatment, the conditions for potassium hydroxide pretreatment of steam exploded soybean hull were optimized by using RSM (response surface methodology). The optimum conditions for minimum lignin content were determined to be 0.6% potassium hydroxide concentration, $70^{\circ}C$ reaction temperature and 198 min reaction time. The predicted lignin content was 2.2% at the optimum conditions. Experimental verification of the optimum conditions gave the lignin content in similar value with the estimated value of the model. Finally, glucose conversion of pretreated soybean hull using acid hydrolysis resulted in $97.1{\pm}0.4%$. This research of two-step pretreatment was a promising method for increasing the glucose conversion in the cellulose-to-glucose process.

Low-Cost Position Sensorless Switched Relutance Motor Drive Using a Single-Controllable Switch Converter

  • Yang, Hyong-Yeol;Kim, Jae-Hyuck;Krishnan, R.
    • Journal of Power Electronics
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    • v.12 no.1
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    • pp.75-82
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    • 2012
  • Elimination of rotor position sensors mechanically coupled with the rotor shaft is attractive to variable speed drives primarily due to increased system reliability and cost reduction. In this regard, search for a simple and robust position sensorless control has been intensified in past few years specifically for low-cost, high-volume applications such as home appliances. This paper describes a new parameter insensitive position sensorless control for switched reluctance motor (SRM) drives satisfying such a need in this market segment. Two consecutive switch-on times of the controllable switch in hysteresis current control are compared to estimate the rotor position and speed. The proposed sensorless control algorithm is very simple to implement since it does not depend on extensive computation or any additional hardware. In addition, the proposed method is robust in that its dynamic performance is least affected by system parameter variations. The proposed approach is demonstrated on a single-controllable-switch-converter-driven SRM with two-phases that lends itself to a system with low cost and compact packaging which comes close to the intended applications. Analysis and simulation results followed by experimental verification are presented to demonstrate the feasibility of the proposed sensorless control method.

An Empirical Study on Emotional Space Design-II (감성공간디자인의 실증적 연구-II)

  • Oh, Young-Keun
    • Korean Institute of Interior Design Journal
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    • v.21 no.1
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    • pp.103-110
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    • 2012
  • With a theoretical focus on the emotional experiences created via the interface, and the relationship between human beings and space, this study aims to corroborate and clarify the formation and verification of emotional interactions between human beings and space using body movements. It follows the method of Coining "Movement Phrases" through the analysis of body movements in the experimental space, thereby developing them into a complete scenario to produce the story of emotional expression. This study has hereby generated the following outcomes: First, the "pocket-type" exhibition displays a higher frequency of body movements than the "general" exhibition. It has close connections with emotional vocabularies: "Curious," "interesting," "warm," and "fun." The "general" exhibition records a relatively high frequency of emotional vocabularies like "natural," "efficient," and "free." Second, it is possible to analyze the story of space using a scenario, just like drama, based upon attributes and serial relationships. The "exposition" section reveals a high degree of "curiosity" and a large number of body movements, while the "development" section indicates high degree of "surprise" plus slight body movements. The "transition" sections manifest high "interest" and many body movements, and the "climax" section shows a high frequency of "surprise" and many changes in body movements. The "conclusion" section finally invokes images together with body movements.

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Computer based FEM stabilization of oxygen transport model for material and energy simulation in corroding reinforced concrete

  • Hussain, Raja Rizwan
    • Computers and Concrete
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    • v.12 no.5
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    • pp.669-680
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    • 2013
  • This paper unveils a new computer based stabilization methodology for automated modeling analysis and its experimental verification for corrosion in reinforced concrete structures under the effect of varying oxygen concentration. Various corrosion cells with different concrete compositions under four different environmental conditions (air dry, submerged, 95% R.H and alternate wetting-drying) have been investigated under controlled laboratory conditions. The results of these laboratory tests were utilized with an automated computer-aided simulation model. This model based on mass and energy stabilization through the porous media for the corrosion process was coupled with modified stabilization methodology. By this coupling, it was possible to predict, maintain and transfer the influence of oxygen concentration on the corrosion rate of the reinforcement in concrete under various defined conditions satisfactorily. The variation in oxygen concentration available for corrosion reaction has been taken into account simulating the actual field conditions such as by varying concrete cover depth, relative humidity, water-cement ratio etc. The modeling task has been incorporated by the use of a computer based durability model as a finite element computational approach for stabilizing the effect of oxygen on corrosion of reinforced concrete structures.

Experimental Verification of Age-adjusted Effective Modulus Method to Long-Term Behavior Estimation of Prestressed Composite Girders (재령보정 유효계수방법에 의한 프리스트레스트 합성거더의 장기거동 실험 검증)

  • Bae, Doo-Byong;Oh, Chang-Kook;Choi, Sok-Hwan
    • Journal of Korean Society of Steel Construction
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    • v.24 no.5
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    • pp.571-582
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    • 2012
  • Prestressed composite girders provide efficient composite action by applying prestress to the sub-encasing concrete. In this study, an enhanced prestressed composite girder with forms suspended from the steel girder is utilized. Long-term behavior of the prestressed composite girder is estimated using age-adjusted effective modulus method, which is verified experimentally using measurements obtained from an in-service bridge. Then, parametric study is carried out to investigate the influences caused by ambient temperature, humidity, prestressing and concrete casting date.

A Technique for Defect Detection of Condenser Tube in Support Plate Region using Guided Wave (유도초음파를 이용한 복수기 튜브지지판 영역에서의 결함검출기법)

  • Kim, Yong-Kwon;Park, Ik-Keun;Park, Sae-Jun;Ahn, Yeon-Shik;Gil, Doo-Song
    • Journal of Welding and Joining
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    • v.30 no.6
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    • pp.36-41
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    • 2012
  • General condensers consist of many tubes supported by tube sheets and support plates to prevent the deflection of the condenser tubes. When a fluid at high pressure and temperature runs over the tubes for the purpose of transferring heat from one medium to another, the tubes vibrate and their surface comes into contact with the support plates. This vibration causes damage to the tubes, such as cracks and wear. We propose an ultrasonic guided wave technique to detect the above problems in the support plate region. In the proposed method, the ultrasonic guided wave mode, L(0,1), is excited using an internal transducer probe from a single position at the end of the tube. In this paper, we present a preliminary experimental verification using a super stainless tube and show that the defects can be discriminated from the support signals in the support region.

Study on Bilateral Exercise Interface Techniques for Active Rehabilitation of the Upper Limb Hemiplegia (상지 편마비 환자의 능동형 재활운동을 위한 양측성 훈련 인터페이스 기법에 대한 연구)

  • Eom, Su-Hong;Song, Ki-Sun;Jang, Mun-Suck;Lee, Eung-Hyuk
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.6
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    • pp.510-517
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    • 2015
  • For the self-directed rehabilitation of upper extremity hemiplegia patients, in this paper we propose an interface method capable of doing bilateral exercises in rehabilitation robotics. This is a method for estimating information of movements from the unaffected-side, and projects it to the affected-side in order. That the affected-side is followed the movements of the unaffected-side. For estimation of the unaffected-side movements information, gyro sensor data and acceleration sensor data were fused. In order to improve the measurement error in data fusion, a HDR filter and a complementary filter were applied. Estimated motion information is derived the one side of the drive input of rehabilitation robot. In order to validate the proposed method, experimental equipment is designed to be similar to the body's joints. The verification was performed by comparing the estimation angle data from inertial sensors and the encoder data which were attached to the mechanism.

Analytical Study on Punching Shear of Reinforced Concrete Flat Plates (철근콘크리트 플랫 플레이트의 뚫림전단 거동에 관한 해석적 연구)

  • Kim, Min-Sook;Lee, Young-Hak;Kim, Hee-Cheul
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.4
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    • pp.409-415
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    • 2010
  • A finite element model for punching shear of flat plate structures is presented. A parametric study also has been conducted to verification of influence of several parameters in terms of the flexural reinforcement ratio, slab thickness. Reisnner-Mindlin assumptions are adopted to consider of shear deformation. Layered shell element is considered for the material non-linearities. The finite element model of this study was verified comparing with existing experimental results. The model is able to predict the capacity of the flat plate structures. The punching shear of flat plate structures varied depending on the flexural reinforcement ratio, slab thickness.

Neural Network-Based Human Identification Using Teeth Contours (치아 윤곽선 정보를 이용한 신경회로망 기반 신원 확인 방안)

  • Park, Sang-Jin;Park, Hyungjun
    • Korean Journal of Computational Design and Engineering
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    • v.18 no.4
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    • pp.275-282
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    • 2013
  • This paper proposes a method for human identification using teeth contours extracted from dental images that are captured from the frontal views of subjects each of who opens his or her mouth slightly. Each dental image has a black-colored region containing the subject's teeth contours which are usually different from subject to subject. This means that this black-colored region has bio-mimetic information useful for human identification. The basic idea of the method is to extract the upper and lower teeth contours from the dental image of each subject and to encode their geometric patterns using a back-propagation neural network model. After acquiring 400 teeth images form 10 university students, we used 300 images for the training data of the neural network model and 100 images for its verification. Experimental results have shown that the proposed neural network-based method can be used as an alternative solution for identification among a small group of humans with a low cost and simple setup.