• Resources Recycling
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• v.5 no.3
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• pp.65-72
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• 1996

Colloidal calcium wrbonate(diametcr 0.02-0 09 m~wja s developed to maintain the mamenl of pnriide formatio~>w ~lhoutsurlace trealment. The control factors of particle size and optimum condiliuna for compound fam*tition has not bccn studiedyet. This shldy war aimed at developing a method fur compounding colloidal calcium carbonfcte to cnl~hol cubic calciumcarbonate, and then compounding the b-o types oI precipitated calcium wrbonatc under optimum wndilrans Calc~umhydroxide was calcinated at 1, lWC far two hours, md then hydrated for 30 minutes at t i i O rprn and ambiznt temperahlle.Two-liter suspension was subjected to the contact with carbon dioxide at l5"C, 600 ipxn and C0= injection in the rate of 1 Umin Two types of dcium carbonate(cuhic calcium carbonatc(0 24.9 pm) md collnidd calcium mhnnate (0.02-0 09 pm))were compounded by "wing the concentrations of calcium oxide and ihe suspension were compounded. It was found that theoptimum concentrations of each suspensions were 5 wt % and 2.5 \I*.% respectively. ' h c key control factor af thc parlicle slzcdislribution was the concenkation al the suspension. The size of compounded particles was measured by a Zcla S k r 'fieaverage particle size of the cubic calcium carbonate aas 223.4 nm(0.223 pm), and that of thc colloidal a~lciumc arbonate was93.6 nm (0.093 km). Ihe particle sizc was evenly cantlolled on a stdblc basis in an H, O reaction system.asis in an H, O reaction system.

• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.600-608
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• 2017

Hazard risk of explosion on pharmaceutical raw materials dust in pharmaceutical industry often exists when it is handled or processed in the industrial sites, and explosion accident is caused by this. In this study, the dust explosion characteristics of the three pharmaceutical raw materials samples were measured. The main explosion characteristics are as follows: $P_{max}$, MIE and MIT of loxoprofen acid having $5.31^{\circ}C$ of median diameter are obtained 8.4 bar, 1 mJ < MIE < 3 mJ and $550^{\circ}C$. $P_{max}$, MIE and MIT of camphorsulfonate having $95.63^{\circ}C$ of median diameter are obtained 7.9 bar, 30 mJ < MIE < 100 mJ and $510^{\circ}C$. $P_{max}$, MIE and MIT of rifampicine having $26.48^{\circ}C$ of median diameter are obtained 7.9 bar and 1 mJ < MIE < 3 mJ and $470^{\circ}C$. The deflagration index ($K_{st}$) and the explosion index (EI) were obtained by using these data. The explosion hazard assessment of pharmaceutical raw materials dust was compared and examined. As a result, the explosion hazard assessment according to deflagration index and explosion index were the explosion class with St 2 and the explosion hazard rating of severe for loxoprofen acid & rifampicine and St 1 and strong for clopidogrel camphorsulfonate, respectively.

• Applied Biological Chemistry
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• v.46 no.2
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• pp.90-93
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• 2003

Physicochemical and gelatinization properties of Suwon-415 pigmented rice starch were determined. The median and mean particle sizes of Suwon-415 pigmented rice starch were 5.23 and $6.27\;{\mu}m$, whereas those of non-glutinous rice starch were 4.71 and $5.43\;{\mu}m$ respectively. Water-binding capacity, iodine reaction and intrinsic viscosity of Suwon-415 pigmented rice starch were lower than those of non-glutinous rice starch. X-ray diffraction patterns showed traditional A type of cereals and relative crystalline of both samples showed no difference. Peak viscosity, breakdown and setback were increased with increasing weight of starches.

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.162-167
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• 1990

10% salted egg yolk containing 12-21% e99 white (RI 42-45) was stored at $-15^{\circ}C\;and\;-25^{\circ}C$. Changes of appearent viscosity and emulsification capacity were measured monthly(1-6 months). Viscosity, oil particle size and emulsion stability of mayonnaise which was prepared with these yolks for each storage time were also tested . In salted e99 yolk, viscosity was increased gradually with increasing the storage time, and further increased in the yolk of less egg white (higher RI), stored at $-25^{\circ}C\;than\;-15^{\circ}C$. Emulsification capacity was decreased gradually with increasing the storage time. In mayonnaise, which was Prepared with these frozen egg folks, oil Particle size became smaller gradually with increasing the storage time of egg folk, and further became smaller in the egg yolks containing low levels of egg white , stored at $-25^{\circ}C\;than\;-15^{\circ}C$. The viscosity of mayonnaise was decreased by about 2 months storage of e99 yolk, and restored thereafter, emulsion stability was decreased by 3-4 months storage of egg yolk and restored slightly thereafter.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.918-922
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• 2008

본 연구에서의 측정 대상인 공주지점은 금강 본류로 홍수 예 경보 지점이며, 그 하상이 대부분 모래로 구성된 충적하천으로 간주된다. 유사량 측정은 강우가 집중되는 6$\sim$9월의 홍수기(25회)와 이를 기준으로 전 후시기인 저 평수기(2회)로 나누어 총 27회로 측정하였고 부유사량(D-74, P-61A: 수심적분법), 하상토(BM-54, 홍수기전 후 2회 채취), 수리량(수위, 유속, 측정수심, 수면폭, 수면경사, 수온)등의 실측자료를 이용하여 미측정구간의 유사량을 포함한 총유사량을 추정(실측+계산; Modified Einstein, 간접계산; Engelund & Hansen, Yang, Ackers & White)하였다. 이러한 분석결과를 가지고 유량-부유사농도와 부유사량 및 총유사량 관계에 대해 살펴보았다. 전체적으로 유량에 대한 측정성과들의 변위와 저유량시 산포도에 있어 다소 큰 경향을 보였고, 주요 강우사상별로 보았을 때 루프(Loop)현상을 볼 수 있었다. 이러한 분석결과의 상충은 하천의 수리, 유사특성과 추정방법의 적용한계 등의 서로 다른 제한된 범위의 자료들을 이용하여 분석하는 데서 오는 차이, 특히 유량, 수심, 하상토의 입경크기 등 자료의 범위가 추정공식들이 추천하는 범위에서 벗어났기 때문인데, 이는 총유사량 공식에 대한 범용성이 적다는 것을 의미한다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.211-212
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• 2003

동북아시아 지역은 최근 급격한 산업화로 인해 대기오염물질의 배출량이 증가하고 있으며, 그 중에서도 중국은 동북아시아에서 가장 높은 비율로 대기 오염 물질을 배출하고 있다. 따라서 중국의 풍하지역에 위치하고 있는 우리나라는 중국에서 배출되는 대기오염물질의 이동, 강하에 의해 영향을 받을 우려가 있다. 입자상 대기오염물질 중에서 입경이 큰 입자들은 강하에 의하여 이동 중에 제거되고, 결국 미세입자가 장거리를 이동하게 된다. 따라서 주로 직경 2.5$\mu\textrm{m}$ 이하의 크기를 갖는 미세입자에 대한 연구가 필요하다. (중략)

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.11
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• pp.1564-1570
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• 1998

In-situ particle monitors(ISPMs) are widely used for monitoring contaminant particles in vacuum-based semiconductor manufacturing equipment. In the present research, the performance of a Particle Measuring Systems(PMS) Vaculaz-2 ISPM at subatmospheric pressures has been studied. We created uniform upstream conditions of particle concentration and measured the detection efficiency, the lower detection limit, and the size response of the ISPM using uniform sized methylene blue aerosol particles. The effect of particle size, particle velocity, particle concentration, and system pressure on the detection efficiency was examined. Results show that the detection efficiency of the ISPM decreases with decreasing chamber pressure, and with increasing mass flow rate. The lower detection limit of the ISPM, determined at 50 % of the measured maximum detection efficiency, was found to be about $0.15{\sim}0.2{\mu}m$, which is similar to the minimum detectable size of $0.17{\mu}$ given by the manufacturer.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.130-131
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• 2007

지방족 액정 계면활성제를 주형물질로 이용, 화학석출을 통해 나노채널을 갖는 금속미립자를 제조하였다. 편광현미경을 이용한 상태도 분석을 통해 헥사고날 구조를 갖는 주형생성 조건을 결정하였으며, 주형의 배열을 방해하지 않고 화학석출이 가능하도록 환원제의 종류, 농도 및 석출방식 등을 조절하였다. 제조된 금속미립자는 입도분석기를 이용하여 평균입경을 측정하였고, TEM 분석을 통해 나노채널의 형성여부를 확인하였다. BET를 이용한 표면적 측정결과, 비표면적이 $112.6m^2/g$로 나노채널 형성으로 인해 비표면적이 크게 증가하였음을 알 수 있었다.

• Journal of Soil and Groundwater Environment
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• v.14 no.6
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• pp.65-70
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• 2009

Reduction of groundwater surface tension prior to air sparging (SEAS, surfactant-enhanced air sparging) was known to increase air saturation in the aquifer under influence, possibly enhancing the removal rates of volatile contaminants. Although SEAS was known to be efficient for increasing air saturation, little information is available for different hydrogeological settings including soil particle sizes and the depth of aquifer. We investigated water saturations in the sparging influence zone during SEAS using one-dimensional column packed with sands of different particle sizes and different aquifer depths. An anionic surfactant was used to suppress the surface tension of water. Two different sands were used; the air entry pressures of the sands were measured to be $15.0\;cmH_2O$, and $36.3\;cmH_2O$, respectively. No significant difference was observed in the water saturation-surface tension relationship for sands with different particle sizes. As the surface tension decreased, the water saturation decreased to a lowest point and then it increased with further decrease in the surface tension. Both sands reached their lowest water saturations when the surface tension was set approximately at 42 dyne/cm. SEAS was conducted at three different aquifer depths; 41 cm, 81 cm, and 160 cm. Water saturation-surface tension relationship was consistent regardless of the aquifer depth. The size of sparging influence zone during SEAS, measured using two-dimensional model, was found to be similar to the changes in air saturation, measured using one-dimensional model. Considering diverse hydrogeological settings where SEAS to be applied, the results here may provide useful information for designing SEAS process.

• Journal of Environmental Impact Assessment
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• v.28 no.5
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• pp.492-506
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• 2019

Heavy metal contaminants in the shooting range are mostly present in a warhead circle or a metal fragment present as a particle, these fine metal particles are weathered for a long period of time is very likely that the surface is present as an oxide or carbon oxide. In particular, lead which is a representative contaminant in the shooting range soil, is present as more fine particles because it increases the softness and is stretched well. Therefore, by physical washing experiment, we conducted a degree analysis, concentration of heavy metals by cubic diameter, composition analysis of metallic substances, and assessment of applicability of gravity, magnetism and floating selection. The experimental results FESEM analysis and the measurement results lead to the micro-balance was confirmed thatthe weight goes outless than the soil ofthe same size in a thinly sliced and side-shaped structure according to the dull characteristics it was confirmed that the high specific gravity applicability. In addition, the remediation efficiency evaluation results using a hydrocyclone applied to this showed a cumulative remediation efficiency of 71%,twice 80%, 3 times 91%. On the other hand, magnetic sifting showed a low efficiency of 17%,floating selection -35mesh (0.5mm)target soil showed a relatively high efficiency to 39% -10mesh (2mm) efficiency was only 16%. The target treatment diameter of soil washing should be 2mm to 0.075mm, which is applied to the actual equipment by adding an additional input classification, which would require management as additional installation costs and processes are constructed. As a result, it is found that the soilremediation of shooting range can be separately according to the size of the warhead. The size is larger than the gravel diameter to most 5.56mm, so it is possible to select a specific gravity using a high gravity. However, the contaminants present in the metal fragments were found to be processed by separating using a hydrocyclone of the soil washing according to the weight is less than the soil of the same particle size in a thinly fragmented structure.