• 산업기술연구
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• 제24권A호
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• pp.251-261
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• 2004

A series of column test with a silty marine soil mixed with Jumunjin Standard Sand were performed to investigate the characteristics of settling and consolidation of non-plastic dredged soils. Column tests were carried out by using the separable column to measure the grain size distribution of consolidated layer. Column tests were performed with changing the mixing ratio of Jumunjin Standard Sand to the silty marine soil, initial water content of slurry and initial height of slurry. Height of interface of slurry was monitored during tests and grain size distribution tests were carried out after finishing tests. Influencing factors on the particle segregation, eventually to the characteristics of settling and consolidation of non-plastic soil, were analyzed on the thesis of test results. As results of column tests, the mixing ratio of sand to the silty marine soil and the initial water content of slurry were known to affect the characteristics of settling and consolidation resulted in significant particle segregation of slurry. Initial height of slurry was found not to affect seriously to particle segregation.

• 한국지반공학회지:지반
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• 제3권3호
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• pp.49-62
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• 1987

우리나라 서해안 반월지역에 산재한 해성토의 침강특성에 대한실험적 연구를 실시하였다. 준설토와 같이 토장자를 다량으로 함유하고 있는 흙의 침강은 자유침강이론만으로 설명할 수 없 다. 따라서 본 연구에서는 Kynch, McRoberts and Nixon의 간섭침강이론을 도입하여 반월해함토의 침강특성을 실험을 통하여 파악하였다. 그 결과에 의하면 초기함수비 1000%에서 간섭침강발생함을 알았다. 또한 침강계면의 하강과 묵 적고의 관계를 시간의 함수로 실험에 의해 그 관계를 확인하였다.

• 환경영향평가
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• 제2권1호
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• pp.57-63
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• 1993

An analysis for particle settling effects via of plume centerline tilted exponentially under the influence of panicle settling velocity is carried out for particle of $30{\mu}m$ diameter with $1g/cm^3$ density and 0.02m/s settling velocity corresponding to its particle characteristic according to various wind speeds, atmospheric stabilities. Characteristic analysis of surface concentration distribution simulated by Lagrangian model also are carried out under the influence of plume centerline tilted exponentially at 10m stack height emitted 200 particles per second. This study reveals that plume centerline at the nearby source is sharply tilted exponentially under the condition of stable, weakly wind speed, therefore the lower concentration at the nearby source, the higher concentration at the downwind distance far away from source than actual one is brought out, if not apply the effect of plume centerline tilted exponentially to diffusion Model.

• 상하수도학회지
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• 제19권3호
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• pp.318-322
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• 2005

We applied a commercially available computational fluid dynamics model, FLOW-3D, to design a settling basin inlet structure for the intended O sewage plant. In addition, we analyzed the extent to which the inlet sewage water was distributed as a result, firstly, of the location and width of a submerged baffle wall and, secondly, of the opening ratio of a baffle wall with opening holes. The application results show that the flow is unstable due to the generation of eddies in both sides of the submerged baffle wall when the submerged baffle wall is located close to the inlet. The eddies and subsequent instability also occur when the submerged baffle wall is located close to the baffle wall with opening holes. Moreover, the discharge that passes through the midsection of the settling basin increases as the width of the submerged baffle wall increases. At the O sewage plant, when the submerged baffle wall with a width of 2.4 m was located 2 m from the inlet structure and the opening ratio of the baffle wall was 7 percent, the most satisfactory distribution of the inlet sewage water occurred at the entrance of the settling basin.

• Ocean Systems Engineering
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• 제13권3호
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• pp.313-324
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• 2023

The vertical distribution of suspended sediments in the mangrove-mud coast is complicated due to the characterization of cohesive sediment properties, and the influence of hydrodynamic factors. In this study, the time-evolution of suspended sediment concentration (SSC) in water depth is simulated by a one-dimensional model. The model applies in-situ data measured in October 2014 at the outer station in Cu Lao Dung coastal areas, Soc Trang, Vietnam. In the model, parameters which have influence on vertical distribution of SSC include the settling velocity Ws and the diffusion coefficient Kz. The settling velocity depends on the cohesive sediment properties, and the diffusion coefficient depends on the wave-current dynamics. The settling velocity is determined by the settling column experiment in the laboratory, which is a constant of 1.8 × 10^-4 ms^-1. Two hydrodynamic conditions are simulated including a strong current condition and a strong wave condition. Both simulations show that the SSC near the bottom is much higher than ones at the surface due to higher turbulence at the bottom. At the bottom layer, the SSC is strongly influenced by the current.

• 반도체디스플레이기술학회지
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• 제22권3호
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• pp.8-13
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• 2023

High bandwidth memory a core technology of the future memory semiconductor industry, is attracting attention. Temporary bonding and debonding process technology, which plays an important role in high bandwidth memory process technology, is also being studied. In this process, total thickness variation is a major factor determining wafer performance. In this study, the reliability of the equipment measuring total thickness variation is identified, and the servo motor settling, and wafer total thickness variation measurement accuracy are analyzed. As for the experimental variables, vacuum, acceleration time, and speed are changed to find the most efficient value by comparing the stabilization time. The smaller the vacuum and the larger the radius, the longer the settling time. If the radius is small, high-speed rotation performance is good, and if the radius is large, low-speed rotation performance is good. In the future, we plan to conduct an experiment to measure the entire of the wafer.

• The Korean Journal of Ceramics
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• 제5권1호
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• pp.30-34
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• 1999

Particle settling behavior was studied by the computer simulation using simultaneous particle condensation and relaxation. This three-dimensional settling algorithm includes the estimation of powder sediment density. Density distribution through the powder sediment was compared and was agreed well with the experimental findings. Settling density depended strongly of the degree of particle relaxation. Sediment strength and isotropy also depended on the degree of particle relaxation. Sever particle bridging was found near sharp corners.

• 한국환경과학회지
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• 제7권5호
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• pp.659-667
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• 1998

In the present paper, batch and semi-continuous settling characteristics of a binary calcium carbonate-water system were investigated. Using experimental data of batch settling characteristics, a graphical analysis for a semi-continuous thickening column was developed and compared with experimental results on the basis of Kynch theory, only where the feed velocity line was within the limits of Kynch theorem III. The analysis showed good agreement with experiments. Quite erroneous results, however, was observed for the analysis of a sludge region on the underloaded operation, which was considered due to the deviation from the limits of theory.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.559-562
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• 2001

There are many engineering applications that demand settling acceleration and volume reduction of fine solid suspensions. It is a matter to Improve the dredged soil thickening as well as the dewatering characteristic, because settling acceleration of dredged soil decreases the scale of industrial process and volume reduction of dredged soil decreases environmetal challenge to the disposal sites. Direct electric current induces the movement of fine solid particles suspended in water. Upon formation of a soil structure, the current further induces the movement of water and contaminant in the soil skeleton. Theses phenomena are known as electrokinetics. This study investigates the viability, of using the technique of electrokinetic dewatering to river dredged soil for settling acceleration and volume reduction. The aspect, such as sedimentation velocity, final volume and current variation are discussed.

• ETRI Journal
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• 제42권5호
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• pp.790-798
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• 2020

Herein, a low-ripple coarse-fine digital low-dropout regulator (D-LDO) without ringing in the transient state is proposed. Conventional D-LDO suffers from a ringing problem when settling the output voltage at a large load transition, which increases the settling time. The proposed D-LDO removes the ringing and reduces the settling time using an auxiliary power stage which adjusts its output current to a load current in the transient state. It also achieves a low output ripple voltage using a comparator with a complete comparison signal. The proposed D-LDO was fabricated using a 65-nm CMOS process with an area of 0.0056 μ㎡. The undershoot and overshoot were 47 mV and 23 mV, respectively, when the load current was changed from 10 mA to 100 mA within an edge time of 20 ns. The settling time decreased from 2.1 ㎲ to 130 ns and the ripple voltage was 3 mV with a quiescent current of 75 ㎂.