• 대한기계학회논문집B
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• 제22권1호
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• pp.50-60
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• 1998

As a method to develop an enhanced heat transfer fluid, the fine particles of a phase-change material were mixed with a conventional heat transfer fluid. Paraffin, which can be obtained easily in domestic market, was used for the phase-change material and water was used as a carrier fluid. Fine liquid particles of paraffin were formed in water as an emulsion by using an emulsifier, and they were cooled rapidly to become solid particle, resulting in paraffin slurry. The average diameter of produced solid particles was inversely proportional to the amount of the added emulsifier, which was theoretically proved. The produced paraffin slurry was tested thermally in heat transfer test section having a constant-heat-flux boundary condition. The test section was made of a circular stainless-steel pipe, which was directly heated by the power supply having a maximum of 50 Volts-500 Amperes. DSC(Differential scanning calorimeter) tests showed that two kinds of phase change were involved in the melting of paraffin, and it was explained in two different ways. A five- region-melting model was developed by extending the conventional three-region-melting model, and was used to obtain the local bulk mean temperatures of paraffin slurry in the heating test section. The local heat transfer coefficient showed a maximum where the bulk mean temperature of the paraffin slurry reached at the melting temperature of paraffin.

• 한국수소및신에너지학회논문집
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• 제26권4호
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• pp.357-362
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• 2015

There is potential method to utilize the liquid carbon dioxide ($LCO_2$) in coal gasification plants. The $LCO_2$ could be used to effectively transport coal particles instead of conventional carrier such as liquid water ($H_2O$) particularly in wet-fed gasifier. However, there is a lack of fundamental study on the atomization behavior of $LCO_2$ coal slurry under high pressure condition. In this study, the flashing spray characteristics of a coal mixture with $LCO_2$ was examined during a throttling process by using a flow visualization system. The spray of coal water slurry which is in the Rayleigh-type break up mode was significantly different. This difference indicates that the coal water slurry did not effectively transport the coal, as compared to $LCO_2$ coal slurry.

• 설비공학논문집
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• 제21권9호
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• pp.496-504
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• 2009

In order to investigate the feasibility of a direct ice slurry transporting system for the purpose of district cooling, a case study of field application is performed. The research aims include the field measurement of ice packing factor, the performance of coldness delivery, and the branching characteristics of ice slurry. Two representative types of pipe branch are dealt with in this work. For the slurry flow with ice volume fraction of 0.16 or less, the pipe blocking due to aggregation is not observed. Based on the time-wise variation of temperature in the storage tank, a calculating method of ice packing factor is newly developed, which seems to be useful when the brine concentration is unknown. It is confirmed that the mass flow rate of ice slurry per unit cooling load is markedly reduced with increasing the ice content. The pumping power also decreases, but remains unchanged for high ice fractions. The distribution of ice particle before and after branching shows a good uniformity within the range of 5% difference, but yields a unique trend depending on the flow rate.

• 한국축산시설환경학회지
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• 제10권2호
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• pp.75-80
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• 2004

본 연구는 액상분뇨 시용방법의 벼의 생육특성, 수량, 수량구성 요소, 쌀 품질에 미치는 영향을 구명하기 위하여 실시되었다. 처리는 액상분뇨를 기비만 처리한 처리구, 액상분뇨를 기비로 시용하고 화학비료를 추비로 시용한 시험구, 대조구로 화학비료 시용구를 두었다. 시험결과를 요약하면 아래와 같다. 1. 초장은 생육초기 화학비료구가 가장 큰 것으로 나타났으나 생육후기에는 초장의 차이가 처리구 간에 크지 않았다. 분얼 수의 경우도 화학비료구가 액비 시용구보다 더 많았다. 엽록소 함량은 생육초기 화학비료 시용구에서 생육 후기에는 처리간에 유의한 차이가 없었다. 2. 수량구성 요소에 있어서 주당수수는 화학비료구가 가장 많은 것으론 나타났다. 수당립수는 액상분뇨 시용구에서 가장 많았으며 천립중은 시비처리구 사이에 차이가 없는 것으로 나타났다. 등숙율에 있어서는 화학비료 시용구가 높은 것으로 나타났다 3. 벼의 정조수량은 화학비료 시용구에서 가장 높았고 액비+화학비료구에서 $3\%$ 액상분뇨 시용구에서 화학비료 시용구 대비 $5\%$ 감수되었다. 4. 쌀 품질은 액상분뇨 시용구와 액비기비 +화학비료 추비구가 화학비료구에 비해 상당히 높게 나타났다. 단백질 함량은 액비 시용구가 화학비료 시용구보다 유의성있게 낮았다. 따라서 쌀 품질 향상에 적절한 양의 액비 시용이 효과가 있는 것으로 나타났다.

• 대한기계학회논문집B
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• 제22권6호
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• pp.888-898
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• 1998

The present study investigated the effects of the experimental parameters on the cooling characteristics of the multichip module cooled by the indirect liquid cooling method using water and paraffin slurry. The experimental parameters are mass fraction of 2.5 ~ 7.5% for paraffin slurry, heat flux of 10 ~ 40 W/cm$^{2}$ for the simulated VLSI chips and Reynolds numbers of 5,300 ~ 15,900. The apparatus consisted of test section, paraffin slurry maker, pump, constant temperature baths, flowmeter, etc. The test section made of in-line, four-row array of 12 heat sources for simulating 4 * 3 multichip module which was flush mounted on the top wall of a horizontal rectangular channel with the aspect ratio of 0.2. The inlet temperature was 20 deg. C for all experiments. The size of paraffin slurry was constant as 10 ~ 40 .mu.m befor and after the experiment. The chip surface temperatures for paraffin slurry with the mass fraction of 7.5% showed lower by 16 deg. C than those for water when the heat flux is 40 W/cm$^{2}$. The local heat transfer coefficients for the paraffin slurry with the mass fraction of 7.5% were larger by 17 ~ 25% than those for water at the first and the fourth row. The local heat transfer coefficients reached to a row-number-independent, thermally fully developed value approximately after the third row. The local Nusselt numbers at the fourth row for paraffin slurry with the mass fraction of 7.5% were larger by 23 ~ 29% than those for water.

• 한국축산시설환경학회지
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• 제20권4호
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• pp.195-200
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• 2014

Liquid fertilization of pig manure slurry is very useful treatment method to recycle organic waste matter as a valuable fertilizer. The solids precipitate and accumulated at the bottom of liquid fertilization tank. The content of nitrogen and phosphate are higher in sediment than pig manure slurry. The pH of sediment was 7.53. S-COD/T-COD ratio of pig manure slurry and sediment were 0.477, 0.29, respectively. The moisture content of sediment of pig manure slurry and sediment were 80.45~83.82%, 97%, respectively. The content of organic matter of sediment was 8.79~10.56%. The content of nitrogen and phosphate of sediment and pig manure slurry were 9,000~11,100 mg/L, 9,100~11,100 mg/L, respectively. The particle size of pig manure slurry was distributed from 2 mm to 0.125 mm. On the other hand. the particle size of sediment was under 0.125 mm.

• 한국입자에어로졸학회지
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• 제12권4호
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• pp.145-150
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• 2016

During the chemical mechanical planarization (CMP) process, slurry that comprises abrasive particles can directly affect the CMP performance and quality. Mainly, the large particles in the slurry can generate the defects on the wafer. Thus, many kinds of filters have been used in the CMP process to remove unwanted over-sized particles. Among these filters, the point-of-use (POU) filter is used just before the slurry is supplied onto the CMP pad. In the CMP research field, analysis of the POU filter has been relatively exceptional, and previous studies have not focused on the standardized filtration efficiency (FE) or filter performance. Furthermore, conventional evaluation methods of filter performance are not appropriate for POU filters, as the POU filter is not a membrane type, but is instead a depth type roll filter. In order to accurately evaluate the POU filter, slurry FE according to particle size was measured in this study. Additionally, a CMP experiment was conducted with filtered slurry to demonstrate the effects of filtered slurry on CMP performance. Depending on the flow rate and the filter retention size, the FE according to particle size was different. When the small and large particles have different FEs, the total filtration efficiency (TFE) can still have a similar value. For this reason, there is a need to measure the FE with respect to the particle size to verify the effects of the POU filter on the CMP process.

• 디지털콘텐츠학회 논문지
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• 제14권1호
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• pp.35-40
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• 2013

연마재와 Coolant를 이용한 슬러리는 그동안 반도체 웨이퍼를 시작으로 태양광 산업의 Wire Saw에서 사용량이 급격히 증가하였다. 이에 본 논문에서는 슬러리를 분리 정제하여, 수세뿐만 아니라 화학적 처리를 통하여 보다 고순도의 실리콘카바이드 분말을 얻어, 마이크로웨이브 건조방식으로 건조하였다. 건조한 슬러리 벌크를 분쇄하고 화학적 처리까지 수행하여 제작한 Powder를 각각 열분석, 입도분석, SEM 촬영, 성분분석, XRF, XRD을 통하여 분석하였다. 본 연구 결과 화학적 처리를 통하여 얻은 Powder의 회수율이 수세 처리를 통하여 얻은 Powder 보다 더 높아지는 것을 알 수 있었다. 태양광 소재 산업에서 발생하는 다량의 슬러리를 통합, 재활용함으로 점차 강화되고 있는 국내외 환경 규제에 적극 대응하고, 관련 소재 산업의 인프라 구축 효과를 기대할 수 있다.

• 한국지반공학회논문집
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• 제22권10호
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• pp.21-32
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• 2006

본 연구에서는 벤토나이트 슬러리의 전기적 특성에 대한 영향인자와 전기전도 메커니즘을 규명하고자 하였다. 벤토나이트 및 흙-벤토나이트 슬러리의 전기전도도는 벤토나이트 함량이 증가함에 따라 뚜렷한 선형적 증가 경향을 나타내어 전기전도도 측정기법이 슬러리에서의 벤토나이트 함량 평가에 적용될 수 있음을 확인하였다. 이때 슬러리의 전기전도도 변화는 주로 벤토나이트에 존재하는 양이온이 용해되어 용액의 전기전도도를 변화시키기 때문에 나타나는 결과로 확인되었다. 슬러리에서 벤토나이트 함량에 따른 전기전도도의 선형적 관계는 용액의 초기 전기전도도와 세립토 함량에 영향을 받는 것으로 나타났으며 이들의 영향을 고려하여 슬러리에서 벤토나이트 함량과 전기전도도와의 관계식을 도출하였다. 본 연구에서 제시된 관계식을 토대로 다양한 조건의 벤토나이트 및 흙-벤토나이트 슬러리에서 전기전도도 측정을 통하여 벤토나이트 함량에 대한 정량적인 평가가 가능할 것으로 기대된다.

• 국제학술발표논문집
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• The 8th International Conference on Construction Engineering and Project Management
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• pp.463-481
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• 2020

Cutter suction dredgers (CSDs) are widely used in various dredging constructions such as channel excavation, wharf construction, and reef construction. During a CSD construction, the main operation is to control the swing speed of cutter to keep the slurry concentration in a proper range. However, the slurry concentration cannot be monitored in real-time, i.e., there is a "time-lag effect" in the log of slurry concentration, making it difficult for operators to make the optimal decision on controlling. Concerning this issue, a solution scheme that using real-time monitored indicators to predict current slurry concentration is proposed in this research. The characteristics of the CSD monitoring data are first studied, and a set of preprocessing methods are presented. Then we put forward the concept of "index class" to select the important indices. Finally, an ensemble learning algorithm is set up to fit the relationship between the slurry concentration and the indices of the index classes. In the experiment, log data over seven days of a practical dredging construction is collected. For comparison, the Deep Neural Network (DNN), Long Short Time Memory (LSTM), Support Vector Machine (SVM), Random Forest (RF), Gradient Boosting Decision Tree (GBDT), and the Bayesian Ridge algorithm are tried. The results show that our method has the best performance with an R² of 0.886 and a mean square error (MSE) of 5.538. This research provides an effective way for real-time predicting the slurry concentration of CSDs and can help to improve the stationarity and production efficiency of dredging construction.