• 대한치과의사협회지
• /
• 제53권11호
• /
• pp.804-816
• /
• 2015

PURPOSE: The aim of this study was to evaluate the influence of the oxide layer removal process in the Co-Cr-Mo (CCM) abutment after casting procedure on the prosthesis settlement and screw stability. MATERIALS AND METHODS: CCM abutments of four different interface conditions (CCM-M; machined, CCM-O; oxide layer formed, CCM-B; blasted, CCM-P; polished after blasted) and gold abutment (Gold-C; Cast with type III Gold alloy) were used. The initial settling values of abutments were evaluated according to the difference of implant-abutment length when the tightening torques were applied at 5 Ncm and 30 Ncm, and the settling values of abutments caused by loading were evaluated according to the difference of implant-abutment length before and after loading with 250 N, 100000 cycle. The loss ratios of removal torque for abutment screws were evaluated according to the difference in value of removal torques under 30 Ncm tightening torque applied before and after cyclic loading. RESULTS: The CCM-P and CCM-B group showed a higher initial settling value compared with the Gold-C group (P<.05), while the Gold-C group showed the highest settling values caused by loading (P<.05) and no significant differences were observed for between CCM groups (P>.05). The loss ratio of removal torque values for the CCM-B, CCM-P groups did not differ significantly from that of the Gold-C group (P>.05). CONCLUSION: Even though the oxide layer was removed by different methods, CCM abutment with internal conical connection structure showed lower abutment settling and similar screw loosening after cyclic loading compared with gold abutment.

• 한국지구물리탐사학회:학술대회논문집
• /
• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
• /
• pp.611-617
• /
• 2003

This study was performed to develop the method for producing industrial coal sources by cleaning Korean anthracite. Laboratory hindered-settling separation column was set and three coal samples were used for tests. Tests were conducted to evaluate the effects of the major operating variables, teeter water flow rate and relative column pressure (set point). Additional tests were performed to elevate the yield and properties of the products using air bubble injecting process. In results, nice products were obtained with high teeter water flow rate and air bubble injection. Also, model of continuous hindered-settling separation process was established to assist the evaluation of the equipment and several operating variables, such as dispersion, teeter water flow rate, feeding rate, etc.

• 한국물환경학회지
• /
• 제23권6호
• /
• pp.934-944
• /
• 2007

Fine suspended solids (SS) induced into a reservoir after flood events play important ecological and water quality roles by presenting persistent turbidity and attenuating light. Thus the origin and physical features must be characterized to understand their transport processes and associated impacts, and for the establishment of watershed based prevention strategies. This study was aimed to characterize the physical properties of the SS sampled from Daecheong Reservoir and its upstream rivers during flood events. Extensive field and laboratory experiments were carried out to identify the turbidity-SS relationships, particle size distributions, settling velocity, and mineral compositions of the SS. Results showed that the turbidity-SS relationships are site-specific depending on the locations and flood events in the system. The turbidity measured within the reservoir was much greater than that measured in the upstream rivers for the same SS value. The effective diameters ($D_{50}$) in the rivers were in the range of $13.3{\sim}54.3{\mu}m$, while those in the reservoir were reduced to $2.5{\sim}14.0{\mu}m$ due to a fast settling of large particles in the rivers. The major minerals consisting of the SS were found to be Illite, Muscovite, Albite, and Quartz both in the rivers and reservoir. Their apparent settling velocities at various locations in the reservoir were in the range of 0.06~0.13 m/day. The research outcome provides a fundamental information for the fine suspended particles that cause persistent turbidity in the reservoir, and can be used as basic parameters for modeling study to search watershed based optimal control measures.

• 한국해안·해양공학회논문집
• /
• 제26권5호
• /
• pp.327-334
• /
• 2014

본 연구에서는 침/퇴적특성 예측/평가를 위한 기초자료 확보를 목적으로 대표적인 준 폐수로인 경인 아라뱃길 주운수로와 연결된 3개 수역(인천해역, 굴포천, 한강수역)에서의 점착성 퇴적물 각각에 대한 침강속도가 실내실험을 통하여 정량적으로 산정되었다. 침강속도 측정결과, 전체적인 농도구간(0.1 < C < 90 g/L)에 걸쳐 굴포천(0.01 < $W_s$ <3.07 mm/s)과 한강수역(0.01 < $W_s$ < 2.97 mm/s) 하상의 점착성 퇴적물은 대체적으로 거의 유사한 크기의 침강속도 분포를 갖는 것으로 나타났으나, 인천해역 표층 점착성 퇴적물은 이들과는 크게 다른 침강속도(0.01 < $W_s$ < 0.92 mm/s) 분포를 갖는 것으로 나타났다. 한편, 각 수역별 퇴적물의 물리화학적 특성 및 해수(혹은 담수)의 특성들의 비교/분석 결과에 따르면, 이러한 인천해역 점착성 퇴적물의 침강속도 분포의 상이함은 주로 유체의 염도 차에 의해 비롯된 것으로 추정되었다.

• 대한토목학회논문집
• /
• 제11권3호
• /
• pp.85-93
• /
• 1991

실트질 접토의 심강(沈降) 특성(特性)에 미치는 초기농도(初期濃度)($C_o$) 및 저면전단응력(底面剪斷應力)(${\tau}_b$)의 효과에 대한 연구를 하기 위해 황해안 영광해역에서 채취한 실트질 점토를 사용하여 순환식 개수로에서 퇴적실험(堆積實驗)을 하였다. 상대농도(相對濃度) $C/C_o$(C=수심 평균한 농도) 및 상대평형농도(相對平衡濃度) $C_{eq}/C_o$($C_{eq}$=평형상태에서 수심 평균한 농도)는 저면전단응력(底面剪斷應力)에 강하게 좌우되며, 초기농도(初期濃度)에는 큰 영향을 받지 않는 것으로 나타났고, 또한 이들 값은 저면전단응력(底面剪斷應力)이 클수록 증가하였다. 황해안 영광해역 퇴적물(堆積物)의 퇴적한계저면전단응력(堆積限界底面剪斷應力)의 최소치는 ${\tau}_{bmin}{\simeq}0.017N/m^2$, 퇴적한계저면전단응력(堆積限界底面剪斷應力)의 최대치는 ${\tau}_{bmax}{\simeq}1.25N/m^2$이며, 이들 값은 퇴적물(堆積物)의 구성성분에 강하게 좌우된다. ${\tau}_b{\geq}{\tau}_{bmin}$ 범위에서 상대농도(相對濃度)($C_{eq}/C_o$)와 겉보기 중앙심강속도(中央沈降速度)($W_{s50}{^{\prime}}$)에 대한 식을 유도하였다. 겉보기 중앙심강속도(中央沈降速度)는 초기농도(初期濃度)보다 저면전단응력(底面剪斷應力)에 훨씬 더 강한 영향을 받고, 저면전단응력(底面剪斷應力)이 증가할수록 지수적으로 감소하였다.

• 한국응용과학기술학회지
• /
• 제14권3호
• /
• pp.29-38
• /
• 1997

Low toxic concentrated oil dispersant using n-Paraffin and Di(ethylene glycol)mono butylether mixed solvent was prepared, and tested by oil dispersant performance test method, and oil dispersant efficiency was measured using vertical shaking method to 3 kinds of Crude oil, Bunker oil and W/O emulsions with different physical properties by appling the prepared dispersant. Although toxicity test was performed with Flat fish and Rock fish by appling the mixed oils emulsified using prepared oil dispersant, couldn't find the toxicity to them. Concentrated oil dispersant prepared has a good dispersion efficiency of 97.2% after 0.5min settling time and 28.3% after 10min settling time to Bunker B oil with 10% water solution. Especially, the concentrated oil dispersant showing the low toxicity to Oryzias Latipes(24hr, TLm) was 54,000 ppm and to Brine Shrimp Artemia(24hr, TLm) was 51,000ppm, and also, it was completely biodegradated to 99.1% after $7{\sim}8$days.

• 한국식품영양과학회지
• /
• 제26권6호
• /
• pp.1013-1020
• /
• 1997

To elicit the effect of fermentation on food quality of the watery Chinese cabbage pickles without fish sauce and red pepper paste(Baik-kimchi), changes in physicochemical properties and microstructure of fiber components were studied. Better water holding capacity(WHC) was showed in Baik-kimchi fermented at $25^{\circ}C$ than that of Baik-kimchi fermented at 5$^{\circ}C$. WHC measured at pH 2 and 6 were ranged from 10.18 to 16.79g/g dried sample for Baik-kimchi fermented at $25^{\circ}C$ and 6.51~14.58g/g dried sample for sample for samples at 5$^{\circ}C$, respectively. The higher WHC was resulted in pH controlled freeze-dried sample to pH 6 than that measured in pH 2 sample. The settling volume(SV) and oil adsorption capacity(OAC) increased with fermentation period and kept the same value for a little while, but slightly decreased in the over ripening period. Baik-kimchi fermented at $25^{\circ}C$ exhibited more shrunk microstructure of parenchyma cell and xylem than those of Baik-kimchi fermented at 5$^{\circ}C$. The appearance of SDF of the both Baik-kimchi ripened at 5$^{\circ}C$ and $25^{\circ}C$ could give granular shape, whereas the overripened Baik-kimchi had smooth surface of SDF. On the other hand, the IDF retained the original shape during fermentation.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 1992년도 가을학술발표회 논문집
• /
• pp.47-54
• /
• 1992

When marine clay is hydraulically dredged from seabed and pumped into the pond enclosed by contatinment dykes, marine clay is mixed and flocculated with water and then settled. At this time, the fines will interact with the water to form a Bingham plastic slurry which has non-Newtonian characteristics. The dredged slurry has different physical properties depending on settling locations and settling depths in the pond and has few hundred percent of water content and almost nil of shear strenght. In order to make this condition of the dredged slurry the final formation for public use within a short period, sand spreading method to enhance the support capacity of the dredged slurry is developed. In this paper, the effect of sand mixing into the dredged slurry of this method is analyzed based on reference study, laboratory tests and actual construction results.

• 상하수도학회지
• /
• 제18권4호
• /
• pp.427-436
• /
• 2004

Sedimentation is one of the most common and important units in conventional water treatment plants. Structure such as various baffle walls and inclined plate settler may be obstacles to the horizontal flow when it is poorly designed. Therefore, the effects of these structures on characteristics of hydraulic flow must be evaluated to improve the settling efficiency of the floc. The hydraulic characteristic of the four sedimentations at the three real WTPs (water treatment plants), which have different structural properties respectively inside the settling basin, were investigated by tracer (fluoride) test. The inclined plate settler installed inside settling basin caused a undesirable impact on horizontal flow and produced dead zone. Intermediate baffle and solid baffle wall under the inclined plate settler at GE plant help to minimize the formation of density currents and flow short circuiting. However, installing perforated baffle under the inclined plate settler at other plants could not induce even distribution of flow. NaF used as a tracer was recovered more than 90% at investigated all basin. Morill index ($t_{90}/t_{10}$), Modal index ($t_p/T-HRT$) and short-circuiting index ($[M-HRT-t_p/M-HRT$) were determined from tracer test results performed at three WTPs. Those indices ranged 2.99~3.45, 0.44~0.72 and 0.23~0.47, respectively.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 1992년도 가을학술발표회 논문집
• /
• pp.61-64
• /
• 1992

Recently, by the lack of fill material, the dredg and fill(hydraulic fill) method is commonly used in reclamation projects. Hydraulic fill method dredges the soil and send it with water through the transportation pipe to the site. The intial state of the hydraulic fill material is accordingly the mixture of water and soil skeleton which settles with time forming a new soil layer. The properties of new soil layer is governed the size of the soil skeleton, the flow velocity of mixing water, salt concentration, the distance from the discharge pipe outlet, and other dredging conditions when settling process occur. In this study, the effects of gradation of derdged soil on the deposition properties (with emphasis on the optimum spacing of the discharge pipes) was investigated by field test. It was found that the soft fine graind soil was forme at 350m from the discharge pipe outlet when the dredged material was classified as CL, while the soft fine grained soil was not formed even at the distance farther than 400m from the diacharge pipe outlet when the dredged material was classified as SM.