• Nuclear Engineering and Technology
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• 제45권2호
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• pp.203-210
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• 2013

The objective of this conducted research is to study the iodine removal efficiency in a self-priming venturi scrubber for submerged and non-submerged operating conditions experimentally and theoretically. The alkaline solution is used as an absorbent, which is prepared by dissolving sodium hydroxide (NaOH) and sodium thiosulphate ($Na2S_2O_3$) in water to remove the gaseous iodine ($I_2$) from the gas. Iodine removal efficiency is examined at various gas flow rates and inlet concentrations of iodine for submerged and non-submerged operating conditions. In the non-submerged venturi scrubber, only the droplets take part in iodine removal efficiency. However, in a submerged venturi scrubber condition, the iodine gas is absorbed from gas to droplets inside the venturi scrubber and from bubbles to surrounding liquid at the outlet of a venturi scrubber. Experimentally, it is observed that the iodine removal efficiency is greater in the submerged venturi scrubber as compare to a non-submerged venturi scrubber condition. The highest iodine removal efficiency of $0.99{\pm}0.001$ has been achieved in a submerged self-priming venturi scrubber condition. A mathematical correlation is used to predict the theoretical iodine removal efficiency in submerged and non-submerged conditions, and it is compared against the experimental results. The Wilkinson et al. correlation is used to predict the bubble diameter theoretically whereas the Nukiyama and Tanasawa correlation is used for droplet diameter. The mass transfer coefficient for the gas phase is calculated from the Steinberger and Treybal correlation. The calculated results for a submerged venturi scrubber agree well with experimental results but underpredicts in the case of the non-submerged venturi scrubber.

• 한국전산유체공학회지
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• 제19권3호
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• pp.8-13
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• 2014

In this study, wave characteristics coming with oblique incident angle to permeable trapezoidal submerged breakwater on the porous seabed are calculated by using boundary element method. This numerical analysis, based on the wave pressure function, is analyzing the continuity in the analytical region including fluid and structure. From the comparison of the reflection coefficients and damping coefficient, the results of this study are in good agreement with the existing results. The peak values of reflection coefficient obtained by permeable trapezoidal submerged breakwater on the porous seabed are smaller than those of permeable trapezoidal submerged breakwater on the non-porous seabed. The velocity vector in front of permeable trapezoidal submerged breakwater on the porous seabed is smaller than that in front of permeable trapezoidal submerged breakwater on the non-porous seabed with out the energy loss.

• 대한치과보철학회:학술대회논문집
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• 대한치과보철학회 1999년도 창립 40주년 기념 추계학술대회
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• pp.139-139
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• 1999

• 대한치주과학회:학술대회논문집
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• 대한치주과학회 2002년도 제42회 종합학술대회 연제초록
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• pp.20-22
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• 2002

• Journal of Periodontal and Implant Science
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• 제40권2호
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• pp.69-75
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• 2010

Purpose: Implant survival rates using a bone-added osteotome sinus floor elevation (BAOSFE) procedure with simultaneous placement of a non-submerged sand blasted with large grit and acid etched (SLA) implant are well documented at sites where native bone height is less than 5 mm. This study evaluated the clinical results of non-submerged SLA Straumann implants placed at the time of the BAOSFE procedure at sites where native bone height was less than 4 mm. Changes in graft height after the BAOSFE procedure were also assessed using radiographs for 5 years after the implant procedure. Methods: The BAOSFE procedure was performed on 4 patients with atrophic posterior maxillas with simultaneous placement of 7 non-submerged SLA implants. At least 7 standardized radiographs were obtained from each patient as follows: before surgery, immediately after implant placement, 6 months after surgery, every year for the next 3 years, and after more than 5 years had passed. Clinical and radiographic examinations were performed at every visit. Radiographic changes in graft height were calculated with respect to the implant's known length and the original sinus height. Results : All implants were stable functionally, as well as clinically and radiographically, during the follow-up. Most of the radiographic reduction in the grafted bone height occurred in the first 2 years; reduction after 2 years was slight. Conclusions: The simultaneous placement of non-submerged SLA implants using the BAOSFE procedure is a feasible treatment option for patients with severe atrophic posterior maxillas. However, the grafted bone height is reduced during the healing period, and patients must be selected with care.

• 상하수도학회지
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• 제26권2호
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• pp.257-264
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• 2012

The concept of a non-contact type of UV disinfection system was introduced in this study. UV lamps and their quartz sleeves hang over the water surface and there is no interface between the sleeve and water. Obviously, there is no fouling. Based on optical laws and other UV distribution models, a detail mathematical model for a non-contact type UV disinfection system was developed in this study. Pathway length of UV light in a non-contact type photoreactor is longer than that in a submerged type photoreactor because the light is more refractive while passing through 3 interfaces of medium. But the pathway length passing through the water media is not significantly longer than that in a submerged type photoreactor so, the absorption of UV light by water is not significantly different from the other system. Due to the reflection effect, UV intensity is rapidly decreased as the horizontal distance from the light source is increased. The reflective attenuation in a non-contact type photoreactor is higher than that in a submerged type photoreactor. These mean that the short photoreactor is advantageous than the narrow-long photoreactor for the non-contact type photoreactor in an optical point of view.

• 대한치과보철학회지
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• 제50권4호
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• pp.292-298
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• 2012

연구 목적: 이 연구의 목적은 임플란트의 직경, 길이 및 디자인의 변화가 임플란트 안정성 지수에 미치는 영향을 비교하는 것이다. 연구 재료 및 방법: 골질차이에 의한 변수를 제거하기 위해 상악골 평균밀도와 유사한 균일한(0.48g /$cm^3$) 밀도를 가진 Polyuretane foam blocks (Sawbones$^{(R)}$, Pacific Research Laboratories Inc, Vashon, Washington)을 이용, 임플란트(Implantium$^{(R)}$, Dentium, Seoul, Korea)를 다양한 직경(${\phi}3.8$, ${\phi}4.3$ 및 ${\phi}4.8$)과 길이(8, 10 및 12 mm)로 식립하여 그 변화가 임플란트 안정성 지수(Implant Stability Quotient, ISQ)에 미치는 영향을 비교하였다. 또 같은 직경과 길이(${\phi}4.3{\times}10mm$)에서 submerged와 non-submerged (SimplelineII$^{(R)}$, Dentium, Seoul, Korea) 디자인이 ISQ 에 미치는 영향을 비교하였다. 식립 회전력의 영향을 배제하기 위해 동일한 35 N의 Torque로 각 실험군당 10개씩 총 60개의 임플란트를 식립하였다. Osstell$^{TM}$ mentor(Integration Diagnostic AB, Sweden)를 이용하여 공진주파수를 측정한 후 ISQ 값으로 기록하였고, 그 결과를 one-way ANOVA와 Tukey HSD test로 분석하였다(${\alpha}$=.05). 결과: 1. 임플란트 직경의 변화는 ISQ에 영향을 미치지 않았으나(P>.05), 임플란트 길이가 증가함에 따라 ISQ도 증가하였다(P<.001). 2. 임플란트 디자인의 변화는 ISQ와 유의한 상관관계를 보여 Submerged 디자인의 ISQ가 non-submerged 디자인보다 높게 나타났다(P<.05). 결론: 임플란트 안정성을 높이기 위해서는 가능한 길이가 긴 임플란트를 식립하는 것이 유리하며, 같은 길이의 임플란트에서 볼 때 Non-submerged 디자인보다 submerged 디자인이 더 높은 ISQ를 얻을 수 있을 것으로 생각된다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 추계학술대회 논문집
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• pp.229-230
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• 2012

The free flexural vibration of a cantilever plate partially submerged in a fluid is investigated. The fluid is assumed to be inviscid and irrotational. The virtual mass matrix is derived by solving the boundary-value problem related to the fluid motion using elliptical coordinates. The introduction of the elliptical coordinates naturally leads to the use of the Mathieu function. Hence, the virtual mass matrix which reflects the effect of the fluid on the natural vibration characteristics is expressed in analytical form in terms of the Mathieu functions. The virtual mass matrix is then combined with the dynamic model of a thin rectangular plate obtained by using the Rayleigh-Ritz method. This combination is used to analyze the natural vibration characteristics of a partially submerged cantilever plate qualitatively. Also, the non-dimensionalized added virtual mass incremental factors for a partially submerged cantilever plate are presented to facilitate the easy estimation of natural frequencies of a partially submerged cantilever plate. The numerical results validate the proposed approach.

• 한국해양공학회지
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• 제26권2호
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• pp.68-78
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• 2012

This study proposes an improved 3-D model that includes a new non-reflected wave generation system for oblique incident and multi-directional random waves, which enables us to estimate the effect of the various wave-types on 3-D wave fields in a coastal area with permeable submerged breakwaters. Then, using the numerical results,the three-dimensional wave field characteristics around permeable submerged breakwaters are examined in cases of oblique incident and multi-directional random waves. Especially, the wave height, mean surface elevation and mean flow around the submerged breakwaters are discussed in relation to the variation of incident wave condition.

• Ocean Systems Engineering
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• 제9권3호
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• pp.219-240
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• 2019

This paper presents the comparison between SFT response with linear and nonlinear cables. The dynamic response analysis of submerged floating tunnel (SFT) is presented computationally with linear and nonlinear tension legs cables. The analysis is performed computationally for two wave directions one at 90 degrees (perpendicular) to tunnel and other at 45 degrees to the tunnel. The tension legs or cables are assumed as linear and non- linear and the analysis is also performed by assuming one tension leg or cable is failed. The Response Amplitude Operators (RAO's) are computed for first order waves, second order waves for both failure and non-failure case of cables. For first order waves- the SFT response is higher for sway and heave degree of freedom with nonlinear cables as compared with linear cables. For second order waves the SFT response in sway degree of freedom is bit higher response with linear cables as compared with nonlinear cables and the SFT in heave degree of freedom has higher response at low time periods with nonlinear cables as compared with linear cables. For irregular waves the power spectral densities (PSD's) has been computed for sway and heave degrees of freedom, at $45^0$ wave direction PSD's are higher with linear cables as compared with nonlinear cables and at $90^0$ wave direction the PSD's are higher with non-linear cables. The mooring force responses are also computed in y and z directions for linear and nonlinear cables.