• 한국환경보건학회지
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• 제22권1호
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• pp.12-20
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• 1996

This study was carried out to investigate the change of average .specific resistance according to suspension concentration for study phenomena occurring during filtration period. As the results of this study, the following conclusions were obtained. The average specific resistance in 1% $CaCO_3$ suspension was showed power function(R=0.99), whereas in TOYO 5C and TOYO 5A paper were made little difference under high pressure. It represented from results that filtration theory in concord with cake filtration was no affected the average specific resistance of filter medium in cake filtration. In case of 0.1% $CaCO_3$ suspension filtration, the TOYO 5C was showed power function, whereas in TOYO 5A paper differently. In the present study, the $P_1$ value was calculated from the average specific resistance by filtration method. Therefore, $P_1$ value were $1.68\times 10^4Pa$, $4.05\times 10^3Pa$, and $3.15\times 10^3Pa$ in $5.3\times 10^4Pa$, $1.3\times 10^4Pa$, and $8.2\times 10^3Pa$, respectively. We concluded that propriety of new filtration theory was also proved.

• 한국환경보건학회지
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• 제21권2호
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• pp.7-11
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• 1995

This study was carried out to investigate the change of average specific resistance according to filtration pressure, suspension concentration and filters for study phenomena occurring in cake filtration. As the results of this study, the following conclusions were obtained. It was estimated that the average specific resistance of filtration Was decreased in proportion to decreased of filtration pressure. But in very pressure, average specific resistance was increased. The average specific resistance value on filter medium by various pressure was showed as same trends under constant suspension concentration. This phenomenon was though that a carrain amount of fine particles in the cake was found to migrate throught the cake in the case of very thin at very low pressure. In relation to the change of suspension concentration, average specific resistance value become low according to decreased in supension concentration.

• Journal of the Korean Wood Science and Technology
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• 제26권4호
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• pp.86-91
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• 1998

The drainage was used to determine the specific filtration resistance for wood and non-wood fibers. The drainage rate is also affected by factors that can be changed on consistency, pressure drop across the mat, basis weight, additives, and viscosity. Recent development of theoretical studies in flow through porous media and filtration operation emphasize the urgent need for more accurate data for porosity and specific filtration resistance. This study was investigated to determine specific filtration resistance of Hw, Sw-BKP and Kenaf fiber by filtration experimental. Freeness levels selected were 150,250,and $350m\ell$ CSF. The average specific filtration resistance decreased as freeness increased and resistance of Sw-BKP was greater than that of Hw-BKP. The filtrate and porosity increased and specific filtration resistance decreased as particle size of fiber increased.

• Korean Chemical Engineering Research
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• 제50권3호
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• pp.535-544
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• 2012

수평 여과매체를 사용한 케이크 여과에서는 침전이 수반된다. 이 침전 현상을 고려하지 않을 경우 여과기간의 케이크 평균비저항 값이 두 배 이상까지도 잘못 측정될 수 있다. 저자의 전번 논문에서는 여과기간에 침전으로 인해 케이크에 들어가는 현탁액의 고체분율이 변화한다는 것을 이론적으로 주장하였으나, 그 변화가 어느 정도인지를 알아내지 못하였다. 이 논문에서는 먼저 여과-투과 실험방법에 대한 분석에서 투과기간에 측정된 케이크 평균비저항 값이 옳다는 것을 여러 방법으로 증명하고, 여과기간에 통상적인 방법으로 측정된 평균비저항 값은 여과가 진행되는 순간의 현탁액의 고체분율 대신 초기 고체분율을 사용하므로 정확하지 못하다는 것을 입증하였다. 여과와 투과에서 측정된 실험값을 사용하여, 여과 진행 동안 침전에 의해 변화한 현탁액의 고체분율을 계산하였다. 그 후 여과 진행 동안 측정한 현탁액의 높이 변화 값과 이 논문에서 새로 만든 수식을 사용하여 여과 진행 중의 현탁액 고체분율을 결정하였다. 두 가지 방법으로 결정된 현탁액의 고체분율을 비교하여 두 가지가 거의 일치함을 입증하였다.

• Korean Chemical Engineering Research
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• 제50권2호
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• pp.317-327
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• 2012

케이크 여과와 고액분리에서 가장 중요한 지표인 케이크 평균 비저항을 결정하는 방법으로 여과실험을 사용하고 있으나 침전 등의 영향으로 정확한 값을 측정하기 어렵다. 이 연구에서는 조금 더 안정된 방법으로 여과 후 형성된 케이크에 입자제거수를 투과시켜 평균 비저항을 측정하는 여과-투과 실험을 제안한다. 탄산칼슘 1 wt% 현탁액을 사용하여 여과-투과 실험을 8종의 여과매체에 대하여 여과매체 1장과 3장, 압력 0.5 기압과 0.2 기압의 조건에서 각 조건 당 3~5회씩 동일한 실험을 수행하였다. 그 결과 여과 후 투과에서도 안정된 투과 속도가 측정됨을 확인하였고, 이를 바탕으로 Ruth의 공식을 분석하여 투과기간의 특징을 구명(究明) 하고 여과기간에 발생하는 침전의 영향을 분석하였다. 그 다음, 여과매체 3종을 선택하여 여과와 투과에서의 케이크 평균 비저항값으로 일원배치법에 의한 분석을 하였다. 분석결과 여과에 의해서는 0.5 기압과 0.2 기압의 케이크 평균 비저항값이 구분되지 않으나, 투과에 의해서는 충분히 구분되었다. 또한 투과기간의 케이크 평균 비저항값들이 여과기간의 그것에 비해 매우 좁은 분포를 가지는 것을 확인했다. 여러 여과매체의 여과 실험결과를 분석하여, 여과매체 저항을 현재의 방법으로 측정하는 것은 큰 의미가 없음을 밝혔고, 유리섬유 여과-투과 실험 결과로 낮은 압력에서 입자의 여과매체 이동 가능성에 대한 분석을 수행했다.

• 대한환경공학회지
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• 제29권1호
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• pp.74-81
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• 2007

본 연구에서는 케이크 여과 장치의 설계와 케이크 여과 이론의 전개에 가장 큰 역할을 하는 평균 비저항값을 새로운 여과 실험방법인 "여과-투과(filtration-permeation) 실험방법"에 의해 측정하였다. 과거부터 사용되어온 전형적인 여과 실험방법에 의해 측정 되는 평균 비저항값을 여과 평균 비저항 $\alpha_{avf}$이라 하고, 이미 형성된케이크에 입자 제거수를 첨가하여 측정한 평균 비저항값을 투과 평균 비저항 $\alpha_{avf}$이라 하였다. 서로 다른 세 가지 현탁액(입자 현탁액, 응집 현탁액, 고분자 현탁액)에 대해서 "여과-투과 실험방법"으로 케이크 여과를 수행하여 여과기간의 평균 비저항값과 투과기간의 평균 비저항값을 계산하였다. 또한 투과기간의 평균 비저항 값을 기준으로 이론적인 여과과정이 연구되었다. 이 연구결과 입자 여과 조작에서 침전의 영향이 무시될 수 없다는 것이 밝혀졌다. 통상적으로는 침전을 무시하고 있다. 또한 입자 여과과정에서 일정하다고 간주되고 있는 현탁액의 고체분율 5도 변화한다. 통상적인 플럭의 여과과정에서는 케이크 내의 고체분율, $S_c$의 값을 정확히 알기 어렵다는 것을 보였다. 이런 중요한 여러 문제점이 "여과-투과 실험방법"을 통해서는 모두 해결 된다는 것을 보였다.

• 펄프종이기술
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• 제32권4호
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• pp.10-17
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• 2000

The change of fiber length, freeness, initial forming drainage velocity, specific filtration resistance, final drainage time and wet web dryness were measured to investigate the effect of the refining load on the drainage characteristics of pulp. The arithmetic average fiber length after refining with higher refining load was shorter than that obtained with lower refining load. Higher refining load decreased initial forming drainage velocity, final drainage time and wet web dryness. The refining load also affected the relationship between freeness and specific filtration resistance, initial forming drainage velocity, final drainage time. It was found that the specific filtration resistance is better than freeness to predict the drainage characteristics of pulp and the wet dryness.

• Fisheries and Aquatic Sciences
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• 제27권7호
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• pp.434-446
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• 2024

The efficacy of Chromolaena odorata leaf flour components (CO) to increase the growth performance, non-specific immune activity, and resistance against Vibrio parahaemolyticus of whiteleg shrimp (Litopenaeus vannamei) culture was evaluated. To this purpose, whiteleg shrimp post larvae were fed on diets supplemented with 0 and a 1.5 g CO/kg diet for 45 days in a pond. After feeding trials, the shrimps were identified for their growth parameters, collected, and injected with V. parahaemolyticus, then their non-specific immune activity and resistance to V. parahaemolyticus was observed for 14 days. Findings showed that CO increased the average body weight (7.71 g, 37%), weight gain (7.69 g, 40%), and specific growth rate (13.23%/day, 5.7%) as compared to the control. In addition, CO supplementation also increases shrimp's hematologic and immune activity (total hemocyte counts [6.8 × 10⁷ CFU/mL, 242.9%], differential hemocyte counts [27%, 142.1%], and prophenoloxidase activity [0.085%, 566.7%]). Finally, shrimp resistance to V. parahaemolyticus infection also increased after CO supplementation, with survival rates of 73.33% as compared to 23.33% for the control. It suggests that C. odorata leaf flour component supplementation at an optimal dose in the diet may be an effective strategy to increase growth and resistance to bacterial disease with reduced mortality in shrimp farms.

• 한국정밀공학회지
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• 제19권8호
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• pp.63-70
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• 2002

In end milling process, the undeformed chip section area and cutting forces vary periodically with phase change of the tool. However the real undeformed chip section area deviates from the geometrically ideal one owing to cutter runout and tool shape error. In this study, a method of estimating the real undeformed chip section area which reflects cutter runout and tool shape error was presented in up end milling process using measured cutting forces. The average specific cutting resistance, Ka is defined as the main cutting force component divided by the modified chip section area. Ka value becomes smaller as the helix angle increases from $30^circC \;to\;40\circC$. But it becomes larger as the helix angle increases from $40^\circ$to 50 . On one hand, the Ka value shows a tendency to decrease with increase of the modified chip section area and this tendency becomes distinct with smaller helix angle.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.318-318
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• 2009

The door stiffness is one of the important factors side impact. Generally, the researches have been conducted on the assembled door module. This study is to analysis the side impact characteristics for automotives door module. The impact characteristics have been determined by door module side impact test machine. To determine the initial, intermediate and peak crush resistances use the plot of load versus displacement and obtain the integral of the applied load with respect to the crush distances specified below for each door tested. The initial crush resistance is the average force required to deform the door through the initial 6 inches of crush. The intermediate crush resistance is the average force required to deform the door through the initial 12 inches of crush. The peak crush resistance will be directly obtained from the plot of load versus displacement since it is the largest force required to deform the door through the entire 18 inches crush distance. The data are used to determine if a specific vehicle or item of automotives equipment meets the minimum performance requirements of the subject Federal Motor Vehicle Safety Standard(FMVSS). FMVSS Static 214, Side impact protection, specifies performance requirements for protection of occupants in side impact crashes.