• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.2 s.110
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• pp.1-10
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• 2005

Removal of fines from fiber furnish by fractionation improves drainage, but decreases fiber bonding in paper. Fines can be again classified by their size such as the fines that passed 150 and 400 mesh screen, respectively. A hypothesis of different properties between these two kinds of fines was tested. Four different furnishes (SwBKP, HwBKP, KOCC, and BCTMP) were refined in two levels, and all their furnish and handsheet properties were compared in respect of their fines. KOCC fines gave the slowest drainage and least contribution to breaking length while BCTMP fines the fastest drainage and the highest contribution to breaking length. Removal of the fines that passed 400 mesh screen gave high improvement in drainage and large decrease in breaking length. Only KOCC fines removal gave more positive results where there were large improvement in drainage but only small decrease in breaking length.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.984-990
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• 2017

Mesh screen modeling and liquid propellant discharge simulation of surface tension tank were performed using commercial CFD software Flow-3d. $350{\times}2600$, $400{\times}3000$ and $510{\times}3600$ DTW mesh screen were modeled using macroscopic porous media model. Porosity, capillary pressure, and drag coefficient were assigned for each mesh screen model, and bubble point simulations were performed. The mesh screen model was validated with the experimental data. Based on the screen modeling, liquid propellant discharge simulation from PMD tank was performed. NTO was assigned as the liquid propellant, and void was set to flow into the tank inlet to achieve an initial volume flow rate of liquid propellant in $3{\times}10^{-3}g$ acceleration condition. The intial flow pressure drop through the mesh screen was approximately 270 Pa, and the pressure drop increased with time. Liquid propellant discharge was sustained until the flow pressure drop reached approximately 630 Pa, which was near the estimated bubble point value of the screen model.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.702-706
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• 1996

Husked barley contained 17.2% dietary fiber and naked barley contained 14.9% dietary fiber. The barley was ground in a Udy cyclotec mill having a 0.5 mm screen and sieved with a 400-mesh screen (38 m openings). Coarse material of naked barley retained by the screen, with a weight yield of 54.1%, contained 7.0% soluble dietary fiber, 13.9% insoluble dietary filer and 20.9% total dietray fiber. As the naked barley flour level increased in bread baking, the water absorption, mixing time, and loaf weight increased, but the loaf volume decreased. Barley flour was added to wheat flour at a replacement level of 10% without a large adverse effect on bread quality, and the dietary fiber content of bread was increased from 3.0% to 5.0%. The soluble dietary fiber content was not changed, but the insoluble dietary fiber content was increased during the baking process.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.97-108
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• 1996

A new type of passive samplers were designed and produced by authors. After evaluating the quality of activated carbon by measuring recovery rate of organic vapors and steadiness of sampling rate, activated carbon with 30 - 35 mesh produced by Company S in Korea was selected. In each passive sampler, an amount of 400 mg of the activated carbon was filled in 25-mm cassette and covered by fixed screen (or wire screen with 100 mesh). In addition to the fixed screen, a wind screen (or wire screen with 300 mesh) was also attached at outer face. The sampling rate of the new Korean passive samplers was estimated Conclusions obtained in the study are as follows. 1. Sampling rates of the newly developed Korean passive samplers were affected by sampling time. For n-hexane, sampling rates of 15- and 60-minute samples were 70.92 and 37.45 ml/min, respectively. Sampling rate of both 200- and 450-minute samples was 25.96 ml/min. It is concluded that, when passive samplers are used for measuring organic vapors, samples be collected longer than 60 minutes. 2. Sampling rate of the passive samplers was also affected by airborne concentration of organic vapors. Lower sampling rates were determined at level of 1/2 threshold limit values (TLVs) recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). It is recommended that sampling rate of the passive samplers be obtained at site by measuring concentrations using both the NIOSH Method and passive samplers simultaneously. 3. When the passive samplers, which collected organic vapors, were exposed to clean air for five hours, there was no significant loss of organic vapors due to reverse diffusion. 4. When samples were stored at room temperature ($21.8{\pm}0.7^{\circ}C$) and refrigerator ($3.8{\pm}0.7^{\circ}C$), there was no significant difference in the accuracy of results. For trichloroethylene and n-hexane, accuracies were within 25 % at both temperatures until seven days. However, poor accuracy exceeding 25 % was indicated in toluene from the first day. It is recommended that samples be stored at freezing temperature below $0^{\circ}C$. 5. Sampling efficiency was significantly affected by direction of the passive samplers. Results of samplers facing wind and down, respectively, were compared. Lower amount of organic vapors were collected when the sampler was oriented down. It is recommended that, when air velocity is low in plants, the passive samplers be oriented to the wind. However, when air velocity is high, the passive samplers be oriented down.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.172-177
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• 1999

Effect of fiber treatment with cellulase (Liftase A40), and with two refining methods (Valley beating and impact refining) on wood fiber and handsheet properties were investigated at three refining levels (300, 400, and 500ml) for two furnishes (NBKP and LBKP). Part of the treated furnishes were classified by 150 mesh screen into fine-free fiber, and fines. Fiber length analysis, WRV, zero-span strength, and other handsheet mechanical properties were compared. The study showed that Liftase A40 lowered the zero-span and the folding endurance of both furnishes (NBKP much more and LBKP much less). Pretreatment with Liftase A 40 followed by refining significantly lowered the fiber length and refining energy to reach to the target freeness. Impact refining, which is done by hitting the fibers vertically with rod at 20% solid content, kept the fiber length increased WRV, and improved handsheet mechanical properties much more than valley beating. Properties of fines from different sources were compared in detail in the study.