• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.2
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• pp.152-161
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• 2024

This paper investigates the manufacturing and fundamental quality characteristics of potassium magnesia phosphate-based non-cement high-volume fly ash repair mortar. To derive the optimal mix for non-cement mortar, the manufacturing characteristics were evaluated based on the magnesia ratio, and the mortar manufacturing characteristics were assessed with the fly ash mixture. Additionally, the non-cement magnesia repair mortar was produced considering the effects of fly ash mixture and basalt fiber. The evaluation results determined the optimal mix of non-cement magnesia repair mortar, and the feasibility was examined through workability and fundamental quality assessments. The optimal magnesia ratio was found to be P:M 1:0.5, with W/B at 30 %. It was also confirmed that mixing FA and basalt fiber improves fiber dispersion and workability. Even with over 50 % FA mixture, the target strength was achieved within six hours, with a flow increase of up to 18 % and a flexural strength decrease of about 1-2 MPa.

• Korean Journal of Food Science and Technology
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• v.34 no.3
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• pp.413-418
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• 2002

The dough was frozen either before or after fermentation at the five different freezing and storage conditions. Although fermentation before freezing was effective for rapid freezing, it reduced bread volume of the dough frozen at both air freezer and liquid immersion freezer. Freezing at the air freezer set to $-70^{\circ}C$ took more time for freezing and resulted in lower bread volume than freezing at the immersion freezer set to $-20^{\circ}C$. Therefore, the freezing in the liquid immersion freezer was more effective to reduce the freezing time and increase the bread volume. At the liquid immersion freezer, the higher temperature was more effective than lower temperature. The doughs frozen in a liquid immersion freezer set to $-10^{\circ}C$ and fermented after de-frosting produced higher bread volume than control unfrozen dough. And also there was no significant difference in bread volume between the control unfrozen dough and the dough frozen in a liquid immersion freezer set to $-10^{\circ}C$, fermented before freezing and re-fermented after defrosting. The longer proof time and greater loaf volume obtained for the dough frozen and stored at the air freezer set to $-70^{\circ}C$. Therefore the optimum process for freezing the dough was freezing immediately after mixing, storing at $-10^{\circ}C$ in a liquid immersion freezer and fermented after defrosting.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.533-542
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• 2016

We investigate fluidization characteristics of the mixture of rice husk, silica sand and rice husk ash as a preliminary study for valuable utilization of rice husk ash obtained from gasification of rice husk in a fluidized bed reactor. As experiment valuables, the blending ratio of rice husk and sand (rice husk: sand) is selected as 5:95, 10:90, 20:80 and 30:70 on a volume base. Rice husk ash was added with 6 vol% of rice husk for each experiment and air velocity to the reactor was 0~0.63 m/s. In both rice husk/sand and rice husk/sand/ash mixture, the minimum fluidization velocity (Umf) is observed as 0.19~0.21 m/s at feeding of 0~10 vol.% of rice husk and 0.30 m/s at feeding of 20 vol.% of rice husk. With increasing the amount of rice husk up to 30 vol.%, $U_{mf}$ can not measure due to segregation behavior. The mixing index for each experiment is determined using mixing index equation proposed by Brereton and Grace. The mixing index of the mixture of rice husk/sand and rice husk/sand/ash was 0.8~1 and 0.88~1, respectively. The optimum fluidization condition was found for the good mixing and separation of rice husk ash.

• Journal of the Korean Electrochemical Society
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• v.26 no.1
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• pp.1-10
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• 2023

The cathode, which is one of the four major components of a lithium secondary battery, is an important component responsible for the energy density of the battery. The mixing process of active material, conductive material, and polymer binder is very essential in the commonly used wet manufacturing process of the cathode. However, in the case of mixing conditions of the cathode, since there is no systematic method, in most cases, differences in performance occur depending on the manufacturer. Therefore, LiMn₂O₄ (LMO) cathodes were prepared using a commonly used THINKY mixer and homogenizer to optimize the mixing method in the cathode slurry preparation step, and their characteristics were compared. Each mixing condition was performed at 2000 RPM and 7 min, and to determine only the difference in the mixing method during the manufacture of the cathode other experiment conditions (mixing time, material input order, etc.) were kept constant. Among the manufactured THINKY mixer LMO (TLMO) and homogenizer LMO (HLMO), HLMO has more uniform particle dispersion than TLMO, and thus shows higher adhesive strength. Also, the result of the electrochemical evaluation reveals that HLMO cathode showed improved performance with a more stable life cycle compared to TLMO. The initial discharge capacity retention rate of HLMO at 69 cycles was 88%, which is about 4.4 times higher than that of TLMO, and in the case of rate capability, HLMO exhibited a better capacity retention even at high C-rates of 10, 15, and 20 C and the capacity recovery at 1 C was higher than that of TLMO. It's postulated that the use of a homogenizer improves the characteristics of the slurry containing the active material, the conductive material, and the polymer binder creating an electrically conductive network formed by uniformly dispersing the conductive material suppressing its strong electrostatic properties thus avoiding aggregation. As a result, surface contact between the active material and the conductive material increases, electrons move more smoothly, changes in lattice volume during charging and discharging are more reversible and contact resistance between the active material and the conductive material is suppressed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.1
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• pp.90-99
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• 2015

This study examined dynamic and characteristics and chloride penetration of concrete mixed with large amount of FA and BFS, which are considered for positive application to construction fields with purpose of long-tern durability of concrete structures. As a result of strength test on FA and BFS, FA concrete showed higher increase of strength compared to OPC, when FA4000 and FA5000 were mixed 30%, respectively. For BFS concrete, those mixed with 30% and 50% of BFS8000, respectively, showed higher or equivalent strength compare to OPC. As a result of test of chloride penetration on FA and BFS, diffusion coefficients of concrete mixed with 30% FA4000 and FA5000, respectively, showed to restrain average 6.5% of diffusion coefficient compared to OPC. And in case of BFS concrete, those mixed with BFS6000 and BFS8000, restrained diffusion of chloride ions 253% and 336%, respectively, compared to OPC. Therefore, Mixing 50% of BFS was most efficient in order to maximize restraint of chloride penetration according to metathesis of large amount. For relation between compression strength and diffusion coefficient of FA and BFS concrete, as strength increased, diffusion coefficient decreased. In this study, when mixing FA and BFS to concrete for long-run durability and restraint against chloride penetration, for FA, mixing it to concrete with less or equivalent 30% of replacement rate was most efficient. And for BFS, as fineness was higher and mixing it to concrete with less or equivalent 50% of replacement rate, there were results of higher strength compared to OPC and more efficient restraint of chloride ions.

• Tribology and Lubricants
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• v.37 no.6
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• pp.232-239
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• 2021

Petroleum is the most consumed energy source in Korea with a usage rate of 38.7% among the available primary energy sources. The price of liquid petroleum products in Korea includes taxes such as transportation·environment·energy tax. Thus, illegal production and distribution of liquid petroleum is widespread because of its huge price difference from that of the normal product and its tax-free nature. Generally, the illegal petroleum product is produced by mixing liquid petroleum with other similar petroleum alternatives. The two kinds of gasoline, common gasoline and premium gasoline, are being distributed in Korea. The premium gasoline is often adulterated with cheaper common gasoline that lowers the octane number of gasoline. It is possible to distinguish them with their color difference, green and yellow for different grade gasoline. However, when small volume of common gasoline is added to premium gasoline, it is difficult to determine whether premium gasoline contained common grade or not. In this study, we inspect gasoline, which is illegally produced by mixing common gasoline to premium gasoline. When the ratio of mixing common gasoline is increased, premium gasoline shows decreasing absorbance at 600 nm and 650 nm under UV-Vis spectrometer. Moreover, the detected intensity (mV·s) of green dye in high performance liquid chromatography (HPLC) was decreased by common gasoline under 0.99 correlation value. The more the common gasoline is mixed, the more olefin and naphthene are detected by gas chromatography. In addition, trimethyl pentane as octane improver, paraffin and toluene are decreased by common gasoline mixing. The findings of this study suggests that illegal petroleum can be identified by analysis of components and simulated samples.

• Archives of Pharmacal Research
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• v.16 no.1
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• pp.57-61
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• 1993

Based on the turbidimetric response of protein with 50% trichloroacetic acid (TCA), this study aims to introduce an assay method for protein in solution. The standard procedure consists of mixing equal volume of sample solution (standard or unknown) with 50%-TCA solution and measuring the absorbance at 450 nm after 20 min. The absorbances of the solutions were almost stable over 120 min at room temperature. This assy method is simple, reproducible, and tolerant to many interfering substances. It can detect less amount than $10\mu$g/ml of bovin serum albumin. The assay method has low protein-to-protein variability over wide range of molecular weight.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.568-570
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• 1999

복잡한 인체기관의 해부학적 형태 및 상대적 관계를 파악하기 위하여 단일 볼륨에 대한가시화 뿐 아니라 다중 볼륨에 대한 가시화가 요구된다. 본 논문에서는 특정기관의 표면을 추출하여 가시화하는 선택적 렌더링 방법과 투명도 가중치 혼합 방법을 이용한 다중 볼륨렌더링 방법을 제안한다. 해부학적 형태로부터 관심부위의 표면을 추출하여 가시화하는 선택적 렌더링 방법은 분할된 외곽선으로부터 거리변환을 통하여 거리볼륨을 생성하고 이를 렌더링하는 방법으로 거리볼륨을 이용함으로써 가시화시간을 가속화시킬 수 있으며, 다중 볼륨 렌더링 방법은 투명도 가중치 혼합방법을 사용한 렌더링 방법으로 심장의 해부학적 형태와 좌심실, 우심실 간의 혼합된 렌더링 결과를 제시한다. 본 제안방법은 단일 볼륨 렌더링의 한계를 극복하여 복잡한 해부학적 형태로부터 관심부위의 형태와 상대적 관계를 효과적으로 나타낼 수 있다.

• Transactions of Materials Processing
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• v.23 no.2
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• pp.75-81
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• 2014

Progressive dies are used for metal stamping during which multiple operations are performed in a sequence. Material is fed automatically from a coil into the press and advances from one die station to the next with each press stroke. Transfer dies are used in high-volume manufacturing for round, deep-drawn, and medium-to-large parts. Several different operations may be incorporated within a transfer die such as blanking, bending, piercing, trimming, and deep drawing. The main challenge in the current study is how to deform a seat cushion panel meeting the design specifications without any defects. A complex automation die manufacturing technology for the automotive seat cushion panel, mixing both semi-progressive die and transfer die for continuous production, was developed.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.549-554
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• 2002

In Powder System, SCC demands high dosage of superplasticizer and a lage amout of powder for suitable fluidity and viscosity. Okamura's method of most representative mixing design method in SCC of Powder-System is unfavorable economically because of using a large amount of powder. In addition, many ready-mixed concrete plants do not use his mix design method and procedure due to complexity for practical application. Therefore, Nan Su proposed more simple mix design method than Okamura's. It had an advantage in simplicity in practical application and required a smaller amount of powders compared with Okamura's method. This paper proposed an optimal mixture proportion of SCC with consideration of Nan Su's method. The new and modified mix design method required a smaller amount of powder than that of Nan Su's. To check the properties of SCC, considered with the requirements specified by the Japanese Society of Civil Engineering.(JSCE)