• Macromolecular Research
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• 제12권5호
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• pp.443-450
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• 2004

We have studied the effects that inorganic zeolite powder have on structurally different copolymer [poly(propylene-co-ethylene)] and terpolymer [poly(propylene-co-ethylene-co-l-butene)] systems and the possibility of preparing suitable porous composite films. The impact strength and yield stress of the composites did not improve upon any further loading of zeolite, but the modulus increased gradually with respect to the filler loading. The experimental modulus of each of the two systems was compared with theoretical models. We performed a morphological study of the filler mixing efficiency and image analysis. The number-, weight-, and z-average air hole diameters were compared with respect to the draw ratio as well as the zeolite loading. The experimental results suggest that these two matrices can provide a new choice for preparing future multiphase polymeric porous films by stretching them unidirectionally. In particular, we suggest that a 40 wt% zeolite loading at a draw ratio of 4 is useful for porous film applications.

• 대한기계학회논문집
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• 제6권4호
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• pp.331-340
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• 1982

Numerical analysis is made on the turbulent heat transfer with suspension of solid particles in circular tube with constant heat flux. The mean motion of suspending particles in mixture is treated as the secondary gas flow with virtual density and viscosity. Our modeling of turbulent transport phenomena of suspension flow is based on this assumption and conventional mixing length theory. This paper gives the evidence that the mixing length models can be extended to close the governing equations for two phase turbulent flow with solid boundary at a first order level. Results on Nusselt numbers obtained by analytical treatments are compared with available experimental data and discussed. They suggest that the most important parameters of two phase turbulent heat transfer phenomena are relative particle diameter to pipe diameter, gas-solid loading ratio, and specific heat of suspending material.

• 물과 미래
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• 제27권4호
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• pp.49-57
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• 1994

하수와 우유를 섞은 합성폐수를 처리하기 위해 회전매체를 이용한 완전혼합활성슬러지 공법의 kinetic constant 값을 산정한 결과, $K_{m}$(유기물제거속도) 값은 저부하의 경우는 3.75~8/hr, 고부하인 경우는 8.57~12.5/hr이며, $K_{e}$값은 저부하인 경우 0.007~0.03/hr, 고부하인 경우는 0.09/hr로, $K_{s}$(내호흡계수) 값은 저부하인 경우 1.73~3.68/hr, 고부하인 경우는 3.84~5.75/hr로 나타났으며, Y 값은 0.46gVSS/g$BOD_{5}$로 산정 되었다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2002년도 추계 학술대회논문집
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• pp.127-132
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• 2002

Numerical and experimental works have been made in order to figure out the physical mechanism of thermal storage system for the determination of optimal design and to enhance the thermal efficiency of the system. To this end a computer program is developed and evaluated successfully against experimental data measured with a bench scale facility. Considering the thermal efficiency of storage is critically impaired by the mixing effect, the minimum flow mixing situation is calculated by the assumption of uniform plug-type flow as a reference condition. Further a parametric systematic calculations have been made for a hypothetical full-scale storage system with Fr, storage dimension, diffuser type and loading hour, etc.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.41-42
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• 2006

Small powder size is very useful in achieving detailed structures. STS 316 nanopowders with an average diameter of 100 nm and $5{\mu}m$ were utilized to produce feedstock. The mixing behavior of the feedstock indicated that the nanoparticle feedstock produced the highest mixing torque at various powder loading compared to the micropowder feedstock. The nanoparticles feedstocks showed that elastic properties are dominant in flow behavior and high viscosity. Conversely the micropowders feedstocks, viscous properties are dominant in flow behavior and less viscosity, nanopowders feedstock perform lower flow activation energy than feedstock with bigger particles.

• 한국재료학회지
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• 제32권4호
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• pp.223-229
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• 2022

A porous photocatalyst concrete filter was successfully produced to remove NOx, by mixing TiO₂ photocatalyst with lightweight aerated concrete. Ultra Fine Bubbles were used to form continuous pores inside the porous photocatalytic concrete filter, which was mixed via a bubble generation experiment. The optimal mixing condition was determined to be with 4 % of the bubble generation agent B. NO removal specimens were prepared for various photocatalytic loading conditions, and the specimen containing 3 % P-25 removed NO at a concentration of 1.03 µmol in 1 h. The NO removal rate of the porous photocatalytic concrete filter prepared in this study was 10.99 %. This photocatalytic filter performance was more than 9 times the amount of NO removed by a general photocatalytic filter. The porous photocatalyst concrete filter for removing NOx developed in this study can be applied to various construction sites and the air quality can be solved by reducing NOx contributing to the formation of fine particles.

• 한국방재학회 논문집
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• 제7권5호
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• pp.11-18
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• 2007

고인성 섬유보강 시멘트 모르터의 휨피로 거동을 규명하고자 실내실험을 실시하였다. 정적 휨실험과 휨피로 실험을 위해 섬유혼입율에 따라 5개의 시험체와 14개의 시험체를 각각 제작하였다. 휨피로 시험에 앞서서 정적 파괴하중과 응력수준을 결정하기 위하여 정적 휨시험이 실시되었다. 피로응력수준과 섬유혼입율에 따른 휨피로 거동을 분석하였으며 휨피로응력수준과 파괴시 하중반복회수와의 상관관계식을 제안하였다.

• Structural Engineering and Mechanics
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• 제56권4호
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• pp.535-548
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• 2015

A series of experimental results on thin mild steel plates clamped at the boundary subjected to gas detonation shock loading are presented. Detonation occurred by mixing Acetylene (C2H2)-Oxygen (O2) in various volume ratio and different initial pressure. The applied impulse is varied to give deformation in the range from 6 mm to 35 mm. Analytical modeling using energy method was also performed. Dependent material properties, as well as strain rate sensitivity, are included in the theoretical modeling. Prediction values for midpoint deflections are compared with experimental data. The analytical predictions have good agreement with experimental values. Moreover, it has been shown that the obtained model has much less error compared with those previously proposed in the literature.

• 대한기계학회논문집
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• 제8권2호
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• pp.133-140
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• 1984

본 연구에서는 이러한 2유체방정식모델을 Stokes의 저항력 뿐만 아니라 벽면 의 영향을 함께 노고하여 벤츄리관에서의 정압강하가 공기류량과 고체유량, 그리고 입 자의 크기에 어떻게 의존하는가를 해석하였다. 본 연구의 수치해석결과를 Farbar와 Lee와 Crowe의 실험과 비교하였으며, 만족할 만한 일치를 얻었다.

• KSBB Journal
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• 제6권1호
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• pp.99-103
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• 1991

본 연구는 혼합 반응기에서 파라-톨루엔 설폰산(PTSA) 용액으로 이소부틸렌의 최적 흡수 속도론과 최적 흡수 조건을 연구하였다. 본 실험에서 행한 실험 조건은 온도 $20-80^{\circ}C$, 혼합속도 400-1000 rpm, 산농도 30-70 wt% 그리고 산부하(acid loading) 0.3-5 이었다. 결과적으로 최적 조건에서의 이소부틸렌의 흡수속도는 이소부틸렌 농도항에 대한 1차 반응이며 PTSA 농도항에 대해서는 반응 차수가 변한다. 그때의 겉보기 활성에너지는 13Kcal/mol 이었다.