• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.199-200
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• 2020

In this study, the effect of porous powders on the dispersibility and strength properties of CNTs was examined.As a result of the experiment, it was found that in the case of incorporation of CNT, the compressive strength property was significantly improved by improving the dispersibility of CNT.

• Journal of the Korean Applied Science and Technology
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• v.29 no.3
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• pp.377-392
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• 2012

It has been known that small solid particles act as a stabilizer in pickering emulsion system. In this study, we successfully prepared stable pickering emulsion in n-hexylalcohol and water system with $TiO_2$ whose surface was treated by alkylsilane. The optimum condition to prepare pickering emulsion stabilized by $TiO_2$ particles was determined by amount of $TiO_2$ particles and ratio of water and oil phase. The type of pickering emulsion was dependent on wettability of particles for water and n-hexylalcohol. When the amount of $TiO_2$ particles increased up to 5.00 wt%, the stability of pickering emulsion was showed to be improved. The most stable pickering emulsion was prepared in the case of W/O type which has the ratio of oil and water phase (3 : 7). We tried to prepare porous $SiO_2-TiO_2$ composite pigments using a pickering emulsion as template at the optimal condition. Porous pigments were synthesized with Ludox HS-30 as an inorganic material by sol-gel process. The characteristics and shape of porous pigments were measured by optical microscope, SEM, BET, XRD and EDS.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.1
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• pp.1-7
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• 2016

Highly porous polymethyl methacrylate (PMMA) microspheres impregnated by $TiO_2$ powder were prepared by spray drying method. The particle size and the porosity were controlled by optimizing the co-solvent ratio and the polymer concentration. $TiO_2$ powder was impregnated into the microspheres upto 74.6 wt% content based on the weight of the resultant $PMMA/TiO_2$ microspheres. SEM images showed that $TiO_2$ powder was well distributed throughout the inside of the microsphere. EDX mapping showed that the Ti signal was well detected from every part of the microspheres, which was the evidence of the formation of the $PMMA/TiO_2$ composite. Hg porosimetry result showed that the porosity was found to be over 50% regardless of the $TiO_2$ contents. The final product was found to have high oil-absorbing capacity and great hiding power, both of which are key properties in designing the microsphere materials for make-up cosmetics application.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.11a
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• pp.59-62
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• 2002

유동층 건조법은 다공판으로 된 베드 위에 피건조물을 두고 아래쪽에서 열풍을 보내어 열풍속에서 재료를 부유시켜 열풍과 혼합함으로써 건조되는 방식으로 분체의 건조에 유효한 건조방법으로 알려져 있다. 열 및 물질 전달이 상당히 커서 건조가 빠르게 일어나고 온도가 균일하며 균일한 건조가 가능하다. 또한 건조장치의 처리용량이 비교적 크고 장치의 구조가 단순하여 건조장치의 경제성과 신뢰성이 우수하다.(중략)

• Membrane Journal
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• v.15 no.2
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• pp.105-113
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• 2005

Silica membranes were prepared on a porous metal sheet by ultrasonic spray pyrolysis method for gas separation at high temperatures. In order to improve the permselectivity, silica was deposited in the sol-gel derived $silica/\gamma-alumina$ intermediate layer by pyrolysis of tetraethyl orthosilicate (TEOS) at 873 K. The pyrolysis with forced cross flow through the porous wall of the support was very effective in plugging mesopores, Knudsen diffusion regime, that were left unplugged in the membranes. At permeation temperature of 523 K, the silica/alumina composite membrane showed $H_2/N_2$ and water/methanol selectivity as high as 17 and 16, respectively, by molecular sieve effect.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.609-616
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• 2021

In this experimental, water-repellent powder, which is a metal salt-based inorganic substance, and natural zeolite powder, which is a pozzolan-based material, were mixed into cement mortar, and their physical properties and resistance to moisture were confirmed. It was confirmed that the test specimen using natural zeolite at the same time had excellent resistance in the water permeation test and the chloride penetration test as compared with the test specimen in which the inorganic metal salt-based water-repellent powder was mixed alone. When a metal salt-based water-repellent powder is used, it cannot be uniformly dispersed inside water due to its insoluble property, and is limited to the surface. When used at the same time as natural zeolite, the setting time at the initial stage of hydration is fast due to the pozzolan reaction, and the water-repellent powder adheres to the porous of the natural zeolite and is evenly distributed inside the test specimen to generate some water resistance.

• Journal of Pharmaceutical Investigation
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• v.27 no.1
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• pp.39-49
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• 1997

Nicotinic acid was mixed with glass powders such as controlled pore glass (CPG), glyceryl controlled pore glass (GPG) and glass beads (GB) at room temperature. The physicochemical properties of nicotinic acid in the various mixtures were examined by differential thermal analysis, X-ray diffraction study. Infrared spectroscopy and BET gas adsorption measurements. The peak area at the melting point from the various mixtures of nicotinic acid and CPG was increased with an increase of nicotinic acid concentration while the broad peak area was remained unchanged in the DTA curve. As shown in the powder X-ray diffraction patterns, the crystalline peaks of nicotinic acid disappeared in mixture with CPG, suggesting the interaction of nicotinic acid and porous powders. It was found that the larger the content of CPG, the higher the ratio of an amorphous state to a crystalline state. BET isotherm showed that as the amount of nicotinic acid was increased, the specific surface area was reduced proportionally to nicotinic acid content of up to 40% and remained constant thereafter. Sublimation of nicotinic acid from the mixture of nicotinic acid and CPG was examined. A large quantity of nicotinic acid was retained in the mixture when stored on various temperatures in vacuo for 10 hours. The nicotinic acid mixtures with CPG or GPG showed a high dissolution rates of nicotinic acid in aqueous solution, especially in the initial dissolution stage. CPG is expected to be a good pharmaceutical excipient to reduce the crystallinity of drugs and to prevent sublimation of drugs.

• Applied Chemistry for Engineering
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• v.24 no.3
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• pp.231-238
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• 2013

In this study, the $TiO_2$ nano spheres were synthesized by Sol-gel method to give an excellent UV-blocking effect and increase waste adsorption. The pH value was adjusted to obtain a superb UV-blocking effect and adsorption capacity due to the high surface area which is the characteristics of porosity. Base treated $TiO_2$ showed outstanding characteristics. The adsorption of gycerine onto the $TiO_2$ sample using TGA resulted in a high surface area of 1.16 mg/mg. This also showed a high reflectance in the UV-A region. In order to find the optimum dispersion, inorganic powder particles were maintained their sizes as 180 nm for about 6 months. The size of particles were measured using ester oil and silicon oil. Overall, the results reveal that $TiO_2$ has an excellent capability sunscreen in the UV-A region and skin waste adsorption.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.04a
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• pp.77-77
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• 2013

최근의 산업활동에서는 신규 원료 개발과 생산 효율성을 높이기 위하여 분체 공정이 증가하고 있는데, 미세 분진의 취급으로 분진운의 형성과 착화가 용이해지므로 분진폭발이나 화재 위험성이 증가하고 있다. 분진을 안전하게 사용하고 저장, 취급하기 위해서는 착화 전의 위험성 지표로서 최저발화온도(MIT ; Minimum Ignition Temperature)를 사전에 파악해 두는 것이 중요하다. 분진농도의 발화온도는 장치 내의 발화위험성이나 분진 취급 공정의 사고예방대책 관리를 위한 실용적 관점에서 중요하게 활용되는 폭발특성값이다. 또한 분진의 발화온도는 분진농도에 의존하며 농도변화에 따른 가장 낮은 온도를 MIT라고 한다. 본 연구에서는 화재폭발사고 빈도가 줄지 않고 있는 Mg 및 Mg-Al합금(60:40 wt%, 50:50 wt%, 40:60 wt%)을 대상으로 조성비율에 따른 최저발화온도를 실험적으로 조사하였다. Mg 및 Mg-Al(60:40 wt%), Mg-Al(50:50 wt%), Mg-Al(40:60 wt%) 시료의 평균입경은 142, 160, 151, $152{\mu}m$이다. MIT실험장치는 IEC 61241-2-1(Methods for Determining the Minimum Ignition Temperatures of Dust, 1994)에 준거하여 제작하여 사용하였다. 실험장치는 가열로, 분진운 시료홀더, 온도조절장치, 압축공기 제어장치 등으로 구성되어 있다. 구체적인 실험방법은 시험분진를 분진홀더에 장착하고 0.5 bar의 압축공기를 0.3 sec 동안 사용하여 일정 온도로 가열된 로의 내부로 분진운을 부유시킬 때에 분진운이 발화하여 가열로 하단부의 개방구에까지 화염이 전파하는지를 디지털비데오카메라로 기록, 평가하여 발화 유무를 판정하였다. Mg합금에 대한 MIT를 측정한 결과 $740^{\circ}C$가 얻어졌으며, Mg-Al(60:40 wt%)의 MIT는 $820^{\circ}C$로 조사되었다. 그러나 Mg-Al(50:50 wt%) 및 Mg-Al(40:60 wt%)에 대해서는 최대 가열로의 설정온도를 $890^{\circ}C$까지로 하여 농도를 변화시키면서 조사하였으나 발화가 일어나지 않았다. 문헌에 따르면 Mg입자 표면의 산화피막은 다공성으로 일정 온도에서 산화반응이 시간에 따라 직선적으로 증가하는데 반하여, Al의 산화피막은 보호 작용을 하여 일정 온도에서 산화반응속도가 표면과 내부의 농도 기울기에 의한 확산속도에 의존한다고 보고하고 있다. 본 연구결과를 토대로 Mg-Al합금의 발화특성을 고찰해 보면, Mg-Al합금에서 자기 전파성이 작은 Al성분의 증가는 착화지연이 증가하여 연소성이 감소하여 최저발화온도의 증가로 이어지는 것으로 추정되었다. 또한 발화온도는 주어진 조건의 온도장에서 분진이 존재하는 시간 길이에 따라 변화하므로, 발화온도를 실험적으로 측정하는 경우에는 측정장치나 방법에 따라 달라지므로 사업장의 현장에 발화온도를 적용하는 경우에는 장치 내의 분진의 존재시간을 고려할 필요가 있다.

• Journal of the Korean Applied Science and Technology
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• v.36 no.2
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• pp.498-506
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• 2019

This study is based on a coating method that provides utilization value as a micronised powder for cosmetic raw materials using natural minerals buried in Bonghwa, Gyeongsangbuk-do in Korea. The mineral powder name is called Buseok, and chemical name is pumice powder. The results of a study on the efficacy of cosmetics are reported by the development of particulate powder to assess the performance of this powder. First of all, in order to coat the surface of this powder with oil, aluminum hydroxide was coated on the particulate surface and then coated with alkylsilan. In addition, it was coated with vegetable oil to prevent condensation of the powder and increase the dispersion in the oil phase. First; the particle size of pumice powder was from 10 to 50mm having porous holes on the surface of the particles. Second; The components of this powder contained $SiO_2$, $Al_2O_3$, $Fe_2O_3$, MgO, CaO, $K_2O_2$, $Na_2O$, $TiO_2$, $TiO_2$, MnO, $Cr_2O_3$, $V_2O_5$. Third: The particles of this powder have a planetary structure and are reddish-brown with porosity through SEM and TEM analysis. Fourth; the far-infrared radiation rate of this parabolic powder was $0.924{\mu}m$, and the radiative energy was $3.72{\times}102W/m^2$ and ${\mu}m$. In addition, the anion emission is 128 ION/cc, which shows that the coating remains unchanged. Based on these results, it is expected to be widely applied to basic cosmetics such as BB cream, cushion foundation, powderfect, and other color-coordinated cosmetics, sunblock cream, wash-off massage pack as an application of cosmetics. (Small and Medium Business Administration: S2601385)