• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.836-841
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• 2008

CFRD (Concrete Faced Rockfill Dam) has been world-widely constructed due to a lot of advantages compared with rockfill dam and recently, sand/gravel materials, instead of crushed rock materials, are also utilized as a main rockfill material to overcome geological and environmental problems. In this paper, the process of water infiltration into the originally unsaturated sand/gravel-fill dam is studied using two-dimensional saturated-unsaturated seepage theory. According to the results of seepage analysis, if the effective drainage zone is installed in the dam, the reservoir water infiltrate into the dam along a downward flow path towards the lower drainage area. The main body constructed with sand/gravel materials, therefore, remains unsaturated.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.280-285
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• 2005

At present, there are several problems related with sand mat which is used as a way to accelerate consolidation settlement, act like an underground drainage layer and increase trafficability simultaneously. First of all, the unbalance oft he demand and supply of sand is the one of the biggest problems, which makes not only price advance of sand but also delays a term of total construction work. Secondly, the damage of ecosystem and scenery is triggered by thoughtless sand dredging or mining. So, the need that the sand for sand mat should be replaced with a new environmental friendly material has been increased. Fiber mat may be one of the proper materials that suits the need. Therefore, we intended to compare the drainage properties of sand mat with those of fiber mat by experimental model tests. On the basis of the test results, fiber mat took shorter period of consolidation than sand mat and it's amount of settlement showed a little bit bigger than the other. In conclusion, the substitutability of fiber mat for sand mat could be placed highly in view of drainage efficiency. Furthermore, when Fiber mat is used, it has an advantage that spoil soil of the construction site or nearby site can be used for the purpose of increasing trafficability in addition to a role of drainage layer.

• 펄프종이기술
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• 제47권6호
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• pp.5-21
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• 2015

The common production methods of nanocellulosic (cellulosic nanofibrils, CNF) materials from wood are being reviewed, together with large scale applications and particularly papermaking applications. The high energy demand for producing CNF has been one particular problem, which has been addressed over the years and can now be considered solved. Another problem was the clogging of homogenizers/microfluidizers, and the different routes to decrease the energy demand. The clogging tendency, related to the flocculation tendency of fibres is discussed in some detail. The most common methods to decrease the energy demand are TEMPO-oxidation, carboxymethylation and mechanical/enzymatic pre-treatments in the order of increased energy demand for delamination. The rheology characteristics of CNF materials, i.e. the high shear viscosity, shear thinning and the thixotropic properties are being illuminated. CNF materials are strength adjuvants that enhance the relative bonded area in paper sheets and, hence increase the sheet density and give an increased strength of the paper, particularly for chemical pulps. At the same time papers obtain a lower light scattering, higher hygroexpansion and decreased air permeability, similar to the effects of beating pulps. The negative effects on drainage by CNF materials must be alleviated through the appropriate use of microparticulate drainage aids. The use of CNF in films and coatings is interesting because CNF films and coatings can provide paper/board with good oxygen barrier properties, particularly at low relative humidities. Some other high volume applications such as concrete, oil recovery applications, automotive body applications and plastic packaging are also briefly discussed.

• Asian Pacific Journal of Cancer Prevention
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• 제15권14호
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• pp.5617-5620
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• 2014

Objective: To evaluate the prognosis of different ways of drainage for patients with obstructive jaundice caused by hilar cholangiocarcinoma. Materials and Methods: During the period of January 2006- March 2012, percutaneous transhepatic catheter drainage (PTCD)/ percutaneous transhepatic biliary stenting (PTBS) were performed for 89 patients. According to percutaneous transhepatic cholangiography (PTC), external drainage was selected if the region of obstruction could not be passed by guide wire or a metallic stent was inserted if it could. External drainage was the first choice if infection was diagnosed before the procedure, and a metallic stent was inserted in one week after the infection was under control. Selection by new infections, the degree of bilirubin decrease, the change of ALT, the time of recurrence of obstruction, and the survival time of patients as the parameters was conducted to evaluate the methods of different interventional treatments regarding prognosis of patients with hilar obstruction caused by hilar cholangiocarcinoma. Results: PTCD was conducted in 6 patients and PTBS in 7 (p<0.05). Reduction of bilirubin levels and ALT levels was obvious after the procedures (p<0.05). The average survival time with PTCD was 161 days and with PTBS was 243 days (p<0.05). Conclusions: With both drainage procedures for obstructive jaundice caused by hilar cholangiocarcinoma improvement in liver function was obvious. PTBS was found to be better than PTCD for prolonging the patient survival.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.969-978
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• 2010

In this study, a laboratory model test on utilization of recycled aggregates and crushed stone as vertical drains to use alternative material of sand in soft ground is performed. The vertical and horizontal coefficient of permeability of the recycled aggregates and crushed stone showed largely 1.2~4.0 times and 3.0~3.3 times greater than sand, respectively. Therefore, it showed enough to be an alternative material to the sand which had been being used as the vertical and horizontal drainage material before. The variations of pore water pressure with time showed constantly regardless of the load in all vertical drainage materials. When water level drops suddenly, the pore water pressure of the recycled aggregate and crushed aggregate is reduced to nearly zero. Therefore, it was applicable to the field because discharge capacity was similarity to that of sand. The settlement in crushed aggregates and recycled aggregate decreases gradually with the load increase. When water level drops suddenly, earth pressure in all drains materials was evaluated the equivalent drainage capacity similarity to sand because it show approaching the nearly zero.

• 농업과학연구
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• 제37권1호
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• pp.97-104
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• 2010

In this study, a laboratory model test on utilization of recycled aggregates and crushed stone as vertical drains to use alternative material of sand in soft ground is performed. The vertical and horizontal coefficient of permeability of the recycled aggregates and crushed stone showed largely 1.2~4.0 times and 3.0~3.3 times greater than sand, respectively. Therefore, it showed enough to be an alternative material to the sand which had been being used as the vertical and horizontal drainage material before. The variations of pore water pressure with time showed constantly regardless of the load in all vertical drainage materials. When water level drops suddenly, the pore water pressure of the recycled aggregate and crushed aggregate is reduced to nearly zero. Therefore, it was applicable to the field because discharge capacity was similarity to that of sand. The settlement in crushed aggregates and recycled aggregate decreases gradually with the load increase. When water level drops suddenly, earth pressure in all drains materials was evaluated the equivalent drainage capacity similarity to sand because it show approaching the nearly zero.

• 펄프종이기술
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• 제31권1호
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• pp.52-60
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• 1999

Drainage rate in wet-end, which has significant influences on the production capacity, product quality and process economics in papermaking, becomes an important factor in the modern high speed papermaking processes owing to increased level of fines contained in today's pulp materials and increased papermaking system closure. A study was carred out to investigate the influence of beating and fines content on natural and vacuum dewatering using a vacuum drainage tester. Increase in beating and accumulation of fines in the stock decreased natural dewatering, Vacuum dewatering effect, however, increased substantially as beating and fines content were increased. But this increase in vacuum dewatering decreased again when a stock is severely beaten or fines content is greater than 35%. Above this level of fines content, mobile fines migrates to the interstices of the forming web to cause sealing or plugging which restrict fluid movement through the web.

• 한국항만학회지
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• 제12권2호
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• pp.329-336
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• 1998

Sandmats are used to dissipate trapped water rapidly from the embankment built on marine soft ground. At present, however, it becomes difficult to obtain qualified sands since natural resources such as river sand are to exhausted. Also, low permeability of sand may cause low degree of consolidation and instability of embankment. In this study, design and construction methods was discussed. Drainage capacities of prefabricated horizontal drains which were installed in highway construction site are investigated in order to find possible substitution for river sands as drainage materials. On the basis of measurement data at the construction site, it was concluded that use of the prefabricated horizontal drains shows satisfactory drainage capacity without instability of embankment.

• 한국광물학회지
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• 제12권1호
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• pp.32-42
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• 1999

Microbial mats, the yellow and reddish brown deposits formed from the mine drainage, occur on the bottom of drain and mine tailing pond of the Ilkwang mine in Pusan, Korea. The constituents of microbial mats and their biomineralization were studied by using XRD, IR, and SEM-EDX. The upper part of the microbial mat is yellow-colored and composed of tube-shaped and small spheroid bacterial materials, which are mainly made up of amorphous and poor-crystalline iron-oxide minerals. The shape and composition of bacterial materials suggest that they are probably belong to iron-oxide mineral aggregates. The iron-oxide minerals of the yellow microbial mats are mainly goethite, but those of the reddish brown microbial mats contain abundant hematite along with goethite. This implies that with the evolution of biomats, goethite may be transformed to hematite.

• 한국소음진동공학회논문집
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• 제27권1호
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• pp.114-120
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• 2017

Water supply and drainage noise in the bathroom is recognized as one of the main noises, along with the floor-impact sounds, in apartment housings. Recently, to solve such noise issues, a new construction method of installing the piping on the slab has been adopted. rather than the traditional method of penetrating the piping through the slab between the upper and the lower bathrooms. However, this new method has limitations due to high costs and constructional difficulties. Therefore, this study was conducted to develop noise reducing piping and elbows, where the noise can be reduced simply by replacing the existing pipings. The noise level was measured in a laboratory by installing the horizontal drainage piping (three types) and the elbows (three types) developed in this study. The results showed that the horizontal pipings reduced the noise level in LAmax by 0.3 dB(A)~1.0 dB(A), as compared to the existing pipings (VG2), indicating an insignificant noise reduction effect. The elbow reduced the noise level in LAmax by 5.5 dB(A) ~ 11.5 dB(A), as compared to the existing elbow (DRF elbow), with the result of reducing the noise level at all frequencies evenly. Consequently, it was shown that using the elbows is more effective in reducing the water-drainage noise from the toilet than using the horizontal pipings.