• Journal of the Korean Geographical Society
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• v.48 no.6
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• pp.819-836
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• 2013

This study aims to compare the inf luences of pretreatment procedures, and refractive and absorptive indices in grain size analysis of sandy samples collected from Sagot Beach, Baengnyeong Island by laser diffraction grain size analyzer, and propose the proper procedure and method in grain size analysis of sandy samples. The analyzed samples do not indicate large differences by the three pretreatment procedures applied in this study. However, the organic matters should be removed by hydrogen peroxide, because the samples without hydrogen peroxide pretreatments show differences from the samples with hydrogen peroxide pretreatments. The results with a refractive index of 1.3 and absorptive index less than 0.01 also indicate differences from those with other indices. Compared to the differences in fine samples, these differences are not significant and thus, it can be concluded that the results in grain size analysis of sandy samples are not greatly influenced by the refractive and absorptive indices. However, other indices out of the ranges should be applied.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.245-245
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• 2019

점착성 유사는 유사가 가지는 점착력에 의해 응집현상을 겪으며 그 크기와 밀도가 변화한다. 유사의 크기와 밀도는 침강속도에 직접적인 영향을 주며 침강속도는 변화는 유사의 거동에 매우 중요한 작용을 한다. 따라서 점착성 유사의 크기 특성을 파악하는 것은 필수적이다. 본 연구는 유사가 가지는 입도분포를 파악하기 위해 통계학적 접근법을 적용하여 분석하였다. 점착성 유사의 입자가 가지는 입도 분포를 구체화한 결과를 유사의 입도 분포를 위한 수치 모의 연구에 적용하여 모의 결과를 향상시키고 유사 문제의 분석에 용이하도록 하려 한다. 통계학적인 방법 중 적합도 검정을 이용하여 실제 점착성 유사의 입도가 어떠한 분포를 모사하는지 분석하였다. 수집된 입도 분포 자료에 적합도 검정 방법 중 Kolmogorov-Sminorv(K-S) 검정을 이용하였으며 유의수준 5%를 통과할 경우 이론 분포가 점착성 유사의 입도 분포를 잘 모사하는 것으로 판단하였다. 점착성 유사의 입도 분포를 수집하고 그 자료를 바탕으로 적합도 검정을 실시한 결과 많은 연구에서 점착성 유사의 입도 분포로 가정하고 있는 Log-normal 분포가 유의수준 5%를 기준으로 적합도 검정을 통과한 경우는 많지 않았다. 본 연구에서 검정한 결과로는 기존에 이용되는 Log-normal 분포는 위치 매개변수를 추가하여 3 매개변수 분포를 사용할 경우에만 점착성 유사의 입도 분포를 모사한다고 판단된다. 향후에는 점착성 유사의 입도 분포를 모사하고 사용함에 있어 Log-normal 분포를 무조건적으로 이용하는 것은 지양하고 점착성 유사가 가지는 특성을 파악하여 어떠한 입도 분포 형태를 나타낼지 미리 예측하여 이론 분포를 가정한다면 수치모형을 통해 점착성 유사의 입도 분포를 모사할 때 그 정확도가 크게 증가할 것으로 판단된다. 또한 점착성 유사의 입도 분포로서 제시한 GEV 분포와 Gamma 분포, Log-normal 분포를 FM 모형에 결합하여 입도 분포를 모의한 후 그 결과를 실제 현장에서 측정된 입도 분포와 비교하는 과정을 통해 실제 어떠한 분포가 가장 적합하게 모의하는지도 검증할 필요성이 있다고 판단된다. 또한 점착성 유사의 입도를 모사하는 분포를 새로 개발하여 사용한다면 점착성 유사의 이동과 특성을 연구할 때 가장 중요한 크기 특성에 대한 많은 정보를 제공할 수 있으며 유사와 관련된 문제를 용이하게 분석할 것으로 판단된다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.3
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• pp.246-253
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• 1999

Grain size distributions of sediment samples were analyzed by the different methods, and the results were compared. Reported data of the bottom sediments from the Korean seas show significant deviations among the institutes, and the inter-lab comparison and calibration procedures are considered to be necessary. Grain size data by different methods show different results. Laser diffraction method provides good precision in replicate analysis, but underestimates the amounts of finer (smaller than 2-3 ${\mu}m$) fraction. Data from particle settling method, on the other hand, represent significant errors in the coarse silt (5-6 ${\phi}$) fraction, and slightly overestimate the clay fraction. In the sieve and pipette methods, best results were taken in 0.5 ${\phi}$ interval of analysis. Especially in the coarse silt fraction, pipette analysis is suggested to be made with 0.5 ${\phi}$ interval. During the dry sieving procedure in 1 ${\phi}$ interval, serious errors occur when large amounts of sample materials were concentrated in a particular sieve.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.5
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• pp.301-310
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• 2013

For analyzing sand grain size, a specialized high-priced instrument has been used, such as sieve shaker, video camera, laser particle size analyzer, and microscope. Among these, the sieve shaker is commonly used because it is not only cheaper than others but also provides reasonable accuracy. However, it takes a long time and makes lots of dust and noise. In this study, a cheaper and easier method which can replace the sieve shaker is proposed. By using a commercial flat-bed scanner and a darkroom box, the sand size distribution can be analyzed. The darkroom box makes sand images clear and protects the glass of the scanner from being scratched. Comparison between the present method and sieve analysis shows that the present method not only has an accuracy comparable to the sieve analysis but also can save time and effort.

• Journal of the Korean Geographical Society
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• v.45 no.5
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• pp.553-572
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• 2010

Grain size analysis of sediments and soils has been regarded as a one of the most important analytical methods in Earth Sciences. The results of grain size analysis by 10 different pretreatment procedures in loess-paleosol sediments are compared in the study. In spite of the most powerful effectiveness of dispersant(sodium hexametaphosphate) on the dispersions of sediments, the effects show large differences by its treatment orders with HCl. It may result from that $Na^+$ ions in the dispersant may not be able to effectively substitute $Ca^{2+}$ ions in the sediments due to the electrostatic forces between $Na^+$ and $Cl^-$ ions in the dispersant and HCl, respectively. Although $H_2O_2$ and HCl are more effective in dispersion than hot water, they do not affect greatly the dispersions. Therefore, the reliable results of grain size analysis can be obtained by selecting the adequate pretreatment procedures most suitable for the purposes of researches and characteristics of sediments.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.35 no.6
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• pp.164-172
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• 2023

The grain size distribution of sand provides crucial information for understanding coastal erosion and sediment deposition. The commonly used sieve analysis for grain size distribution analysis has limitations such as time-consuming processes and the inability to obtain information about individual particle shapes and colors. In this study, we propose a grain size distribution analysis method using smartphone digital images, which is simpler and more efficient than the sieve analysis method. During the image analysis process, we effectively detect particles from relatively low-resolution smartphone digital images by extracting particle boundaries through image gradient calculation. Using samples collected from four beaches in Gyeongsangbuk-do, we compare and validate the proposed boundary extraction image analysis method with the analysis method that does not extract boundaries, against sieve analysis results. The proposed method shows an average error rate of 8.21% at D₅₀, exhibiting a 65% lower error compared to the method without boundary extraction. Therefore, grain size distribution analysis using smartphone digital images is convenient, efficient, and demonstrated accuracy comparable to sieve analysis.

• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.492-492
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• 2007

• Journal of Practical Engineering Education
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• v.13 no.3
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• pp.559-566
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• 2021

The aggregate gradation analysis is a study that evaluates the accuracy of a specific purpose for the aggregate gradation analysis results essential for construction-related major education. This study is to evaluate the effect of aggregate moisture content on aggregate gradation analysis. The change in the moisture content of the aggregate stored in the asphalt plant cold bin and stock piles was monitored for one year, and based on the results, a sample of aggregate with different moisture content was produced. The gradation curve for each aggregate sample was analyzed to evaluate the effect of aggregate moisture content on aggregate gradation analysis. As a result of the gradation evaluation, it was confirmed that as the moisture content increased, the particle size error for particles less than 5 mm increased in the gradation analysis of the oven-dried aggregate, and this error increased as the particle size decreased. In addition, for aggregate particles of 5 mm or more, it was confirmed that the error in gradation analysis rapidly decreased due to the increase in the moisture content. An analysis was performed on the effect of the error in gradation analysis on the management of hot-bin aggregates in asphalt plants. As a result of the analysis, it was found that the minimum aggregate size of the first hot-bin in a general asphalt plant was 2.38 mm or more, so the maximum gradation error due to the non oven-dry aggregate was less than 2%. Therefore, it seems possible to use the results of the gradation analysis of cold bin non oven-dry aggregate for quality management of asphalt mixture production.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.387-390
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• 2006

매립장주변의 대수층 특성과 수리지화학적 특성과의 상관관계 분석은 매립장 환경 위해 요인을 평가하는데 중요한 역할을 하며 이를 위해 생활쓰레기 매립장인 금산 매립장을 대상으로 연구를 수행하였다. 대수층 매질 특성을 파악하기 위해 토양시료를 채취하여 중금속 성분 및 pH, 전기전도도, 용존유기탄소, 양이온교환능력, 유기물함량, 토양 입도분석을 수행하였고, 수리지화학적 특성 파악을 위해 수질검층 및 지하수 시료를 분석하여 매립지역의 수직 및 수평적인 분포 특성을 파악하였다. 대수층의 토양특성과 지하수 수질특성의 비교분석 결과 침출수 집수정을 기점으로 침출수의 영향을 받은 관측정의 전기전도도(EC) 측정값이 배경 지하수에 비해 상대적으로 높은 값을 보여 주었다. 입도분석 결과 상부 표토에 가까운 50cm 이내의 토양은 농경의 영향으로 심부보다 상대적으로 실트질 토양이 많고 이보다. 심부의 토양은 사질 토양으로 되어 있었다. 이러한 투수성이 좋은 사질 토양은 지하수의 이동을 비교적 쉽게 유도하기 때문에 매립장으로부터 침출수가 누출되었을 때 지하수 흐름을 따라 빠르게 이동할 수 있는 통로로 작용될 것으로 판단된다.

• Cement
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• s.39
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• pp.31-35
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• 1970