• 한국환경보건학회지
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• 제49권6호
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• pp.305-311
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• 2023

Background: The National Institute of Environmental Research (NIER)'s classification of and airborne fraction ratio for consumer chemical products (CCP) does not reflect the characteristics of various product classifications. Objectives: The purpose of this study was to reclassify the types of spray products according to the diverse spray characteristics of CCPs to evaluate the airborne fraction ratio of representative spray types and to compare them with previous CCPs types and airborne fraction ratios. Methods: One thousand seven hundred two products were selected through market research, and 932 newly reported products were selected. After that, 200 were selected to evaluate products with potential inhalation exposure. After classifying six product types that are expected to show differences in the airborne fraction ratio according to the type of product, a final 38 products were selected for use in the airborne fraction ratio through random sampling. Results: CCP has been reclassified from two to six types so that the characteristics of all products are well-reflected. The NIER simply had two airborne fraction ratios, but the results of experiments with six types of products showed a significant difference in values (p<0.01). Airborne fraction ratios of propellant general foam, pump general aerosol, and pump trigger foam in spray type, which were not previously present in NIER, were 7.1%, 24.4%, and 3.5%, respectively. Conclusions: For the diversified types of CCPs, the newly proposed classification was more appropriate than the existing NIER classification. The airborne fraction ratio was also different for each type, so a new value was suggested.

• 한국해안·해양공학회논문집
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• 제29권6호
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• pp.369-381
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• 2017

쇄파역에서 흔히 관측되는 왜도된 비선형 파랑은 정현파에 비해 상대적으로 큰 관성력을 지녀 투과율에 미치는 영향이 상당할 것으로 추정되어왔다. 본고에서는 이러한 추론을 확인하기 위해 왜도가 1.02에서 1.032에 분포하는 총 여섯 개의 파랑을 대상으로 한 수치모의를 수행하였다. 수치모의는 OpenFoam 기반 Tool box인 ihFoam을 사용하여 수행하였으며, 왜도된 비선형 파랑은 경사가 1:30인 천퇴를 이용하여 유도하였다. 투수층에서의 유동은 Navier Stokes Eq.에 추가 항력을 도입하여 해석하였으며, 모의결과 왜도된 비선형 파랑은 정현파에 비해 큰 관성력으로 인해 상대적으로 큰 투과율을 지니는 것으로 모의되었다. 또한 Porous층에서의 Damping으로 인한 파속변화 여부를 살펴 보기위해 Damping이 반영된 천수방정식으로부터 분산관계식을 새로이 유도하였으며, 그 결과 투과성 방파제에서의 파형과 마찰력 사이의 위상차가 파속에 영향을 미치는 것으로 보인다.

• Fibers and Polymers
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• 제5권2호
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• pp.160-169
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• 2004

Polystyrene/layered silicate nanocomposites were prepared by melt intercalation. To examine the distribution of the clay in polymer matrix, small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) were used. Intercalated nanocomposites were obtained and their rheological properties were investigated. Microcellular nanocomposite foams were produced by using a supercritical fluid. As clay contents increased, the cell size decreased and the cell density increased. It was found that layered silicates could operate as heterogeneous nucleation sites. As the saturation pressure increased and the saturation temperature decreased, the cell size decreased and the cell density increased. Microcellular foams have different morphology depending upon the dispersion state of nanoclays.

• 한국산업융합학회 논문집
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• 제23권3호
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• pp.393-401
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• 2020

According to the research and investigations performed on Port Facilities for cargo-works of hazardous materials around the Port of Busan, a conclusion was drawn that the manually operating foam tower monitors are ineffective as they are hard to access due to the radiant heat under contingency circumstances such as a fire. Moreover, in some cases, the effective range of Foam Tower Monitors are insufficient to reach docked ships and manifolds where hazardous materials are being unloaded. In addition, Dangerous Goods freights are inadequately and inefficiently stored regardless properties of hazardous substances due to complicated local regulations, and some are equipped with inapplicable facilities for docked ships. Therefore, in order to effectively counteract the contingencies and obtain safety, it would be recommended to install adequate facilities.

• 한국대기환경학회지
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• 제26권1호
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• pp.77-84
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• 2010

The diffusion and partition coefficients of polyurethane foam (PUF) are estimated using a microbalance experiment and small chamber test. The microbalance is used to measure sorption/desorption kinetics and equilibrium data. When the diffusion condition is controlled in the chamber of the sample, interactions between volatile organic compounds (VOCs) and PUF can lead to the estimation of a relatively homogenous rate of mass transfer in the interiors and surfaces of PUF. The estimates of the material/air partition coefficient (K) and the material-phase diffusion coefficient (D) are shown to be independent of the concentrations of VOCs. This approach, if applied to a diffusion-controlled or physically-based model, can facilitate more precise prediction of their source/sink behavior. Although further research and more rigorous validation is needed, an emission model applied with the diffusion and partition coefficients from this research holds promise for the improvement of reliability in predicting the behavior of VOCs emitted from porous building materials by D and K.

• Environmental Engineering Research
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• 제12권2호
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• pp.81-91
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• 2007

A membrane bioreactor (MBR) was used to investigate the aerobic degradation of foam active substance - non-ionic surfactant, APG 2000 UP. The surface aeration using the propeller loop reactor (PLR) guaranteed sufficient $O_2$ for substrate removal and bacteria growth and avoided foam development. Moreover, the cross-flow membrane filtration enabled the separation of the bacteria still loaded with surfactant in the collecting container. The biological degradation of the surfactant with varying hydraulic retention time (HRT) and influent concentration $c_{S0}$ showed high substrate removal of nearly 95% at high volumetric loading rates up to $7.4\;kgCOD\;m^{-3}d^{-1}$ and at sludge loading rates up to 1.8 kgCOD $(kgVSS\;d)^{-1}$ for biomass concentration $c_B\;{\approx}\;constant $. The increasing $c_B$ from 3.4 to $14.5\;gL^{-1}$ TSS respectively sludge retention time (SRT) from 5.1 to 442 d under complete biomass retention by the membrane filtration resulted in high removal of substrate ${\alpha}\;>\;90%$ with reducing excess sludge production.

• 한국전산유체공학회지
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• 제22권1호
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• pp.95-102
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• 2017

Debris flow is a composition of solid objects of various sizes, suspension and water, which occurs frequently as the results of landslide following heavy rainfall. This often causes extensive damage in the form of socio-economic losses and casualties as witnessed during the incident around Mt. Umyeon, Seoul in 2011. There have been numerous investigation to mitigate the impacts from debris flow; however, the estimation as preparedness measure has not been successful due to nonlinear and multiphase characteristics of phenomena both in material and process inherent in the debris flow. This study presents a numerical approach to simulate the debris flow using open source code of computational fluid dynamics, OpenFOAM with non-Newtonian viscosity model for three phase material modeling. In order to validate the proposed numerical method, the quantitative evaluations were made by comparisons with experimental results and qualitative analysis for the dispersion characteristics was carried for the case of debris flow in the actual incident from Mt. Umyeon.

• 대한골관절종양학회지
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• 제5권3호
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• pp.190-193
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• 1999

Benign fibrous histiocytoma is characteristically composed of fibroblastic and histiocytic cells. Most commonly, this tumor occurs in the dermis and superficial subcutis, but it is uncommon in the knee. We experienced a case of deep benign fibrohistiocytoma in a 38-year-old woman who complained of palpable tender mass on the medial aspect of the right knee. MR imaging findings included a well-delineated oval mass with low signal intensity on T1-weighted and high-signal intensity of T2-weighted images, as well as a marked peripheral contrast enhancement. Histopathologically, the lesion contained a mixture of fibroblastic and histiocytic cells that were often arranged in a cartwheel or storiform pattern and accompanied by varying numbers of inflammatory cells, foam cells, and siderophages. After surgical removal of the lesion, no recurrence was observed.

• 한국전산유체공학회지
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• 제20권2호
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• pp.23-36
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• 2015

The $2^{nd}$ generation ice accretion analysis program has been developed and validated for various icing conditions. The essential feature of the $2^{nd}$ generation code lies in its capability of handling general 3-D geometry and improved accuracy. The entire velocity fields are obtained based on Navier-Stokes equations in order to take the massively separated flow field into account. Unlike $1^{st}$ generation code, the droplet trajectories are calculated using Eulerian approach, which is adopted to yield appropriate collection efficiency even in the shadow region. For improved thermodynamic analysis on the surfaces, water film model and modified Messinger model are newly included in the present analysis. The ice shape for a given time step is obtained by considering the exact amount of ice accreted on the surface. Each module of the icing analysis code has been seamlessly integrated on the OpenFOAM platform. The developed code was validated against available experimental data for 2D airfoils and 3D DLR-F4. Due to the lack of experimental data, the computed results of DLR-F4 were compared with those obtained from FENSAP-ICE, which is state-of-the-art 3D icing analysis code. It was clearly shown that the present code produces comparable results to those of FENSAP-ICE, in terms of prediction accuracy and the capability of handling general 3-D geometries.

• 한국식품과학회지
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• 제24권3호
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• pp.294-299
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• 1992

본 연구에서는 분리대두단백질에 단백질 가수분해효소를 처리하여 대두단백질에 가수분해적 변성을 야기하여 그 기능성을 변화 고찰하고 실제 식품에의 이용방법으로 효소처리된 두유로 두부를 만들어 물성실험과 관능평가를 실시하였다. 장엽에서 SPI를 제조한 후 15분간 bromelain으로 처리하여 2.7% 가수분해된 MSPI를 만들어 기능특성을 측정 비교하였다. MSPI는 전 pH범위에서 용해도가 증가하였고, 특히 등전점에서 15% 정도 증가하였다. 유화형성력과 기포팽창력은 증가하였으나 이들의 안정성은 감소하였는데, 특히 기포안정성은 알칼리쪽에서 급격히 감소하였고, 등전점에서는 가장 큰 것으로 나타났다. 표준두유와 변형두유를 혼합하여 제조한 두부로 물성실험과 관능평가를 실시하였을 때 압착실험에서는 변형두부I이 연하고 탄력성 있는 두부를 형성하는 것으로 나타났다. 각 두부의 물성모형은 spring 한개와 Maxwell 모형 세개를 가진 7요소모형으로 동일한 물성모형을 나타내었다. 관능평가에서는 표준두유와 변형두유를 3 : 1의 비율로 혼합하여 제조한 두부의 품질이 가장 우수한 것으로 평가되었다.