• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.56-57
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• 2019

Recently, the risk of fine dust is emerging in Korea. According to the OECD report, the incidence of hospitalization and mortality from lung disease is increased, and the incidence of lung cancer and mortality from ischemic heart disease with prolonged exposure are increased. In addition, indoor air quality has become an important factor affecting the human body as indoor life has increased due to the Industrial Revolution. Air pollutants that cause indoor air deterioration typically include particulate dusts as described above, formaldehyde and VOCs released in gaseous form from adhesive wood products used in building materials and furniture. May cause breathing problems. In this study, we analyzed the properties of adsorption matrix for improving indoor air quality using cork.

• 한국주거학회논문집
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• 제25권2호
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• pp.19-26
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• 2014

The number of elderly who wants to access to Nursing Homes (NH) will increase due to the rapid aging society and domestic changes. Those who move into NH expect 24/7 care service in safe environment. Providing space free from danger, especially from fall, for the frail elderly is essential. The purpose of this study is to categorize performance needs of flooring materials in the aspect of safety, and analyze materials so that adequate ones for each space in NH can be suggested. Performance needs are as follows; slip resistance (dry/wet), fire resistance, resilience, water resistance, soil retardant, anti-bacterial, gloss, sound absorbtion. maintenance, durability, ease replacement, color and pattern variety, visual and tactual texture, tactile warmth, IAQ, sustainable material (before use), impact to nature (after use). They are categorized under function, economy, sensibility and sustainability. It was found that there are better materials than common ones that has been used repeatedly in NHs, such as vinyl sheets and VCT. In overall, Cork flooring and nylon carpet met all four categories, followed by wool carpet, rubber and linoleum. For bedroom, wood flooring, Cork, rubber, wool carpet, nylon carpets were suggested. In bathroom with shower, rubber, vinyl sheet and porcelain tiles were safe materials. As living/dining room and corridor floors, wool carpet, nylon carpet, cork flooring would be excellent as they are resilient and durable. The result of this paper can be used by both NH managers and material companies, resulting better quality of life of the elderly by providing safe environment.

• 한국약용작물학회지
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• 제20권3호
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• pp.159-164
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• 2012

In this study, we investigated the antibacterial activity, antioxidative activity and whitening effect of 75% ethanol extracts from different parts of Prunus sargentii. The total phenolic compound content of the branch extract was 277.92 mg/g as the highest level. In the measurement of DPPH radical scavenging ability, $SC_{50}$ values of the cork layer and branch extract were 26.79 ${\mu}g/m{\ell}$ and 30.13 ${\mu}g/m{\ell}$. In nitric oxide (NO) scavenging ability, $SC_{50}$ values of the branch and leaf extract were 49.19 ${\mu}g/m{\ell}$ and 55.55 ${\mu}g/m{\ell}$. All extracts exhibited higher NO scavenging ability than ascorbic acid used as positive control. On the other hand, in antibacterial activity against Staphylococcus epidermidis and Staphylococcus aureus by disc diffusion assay, the pure bark extract showed the highest activity. Moreover, tyrosinase inhibitory activity of cork layer, pure bark and branch extracts showed higher activity than arbutin used as positive control. In the cytotoxicity measurement by MTT assay, leaf extract was exhibited Raw 264.7 cell viabilities of 44.68~61.83% as cytotoxic result in tested concentration. In conclusion, the branch extract of Prunus sargentii will be a functional materials without damage compared to other parts such as pure bark or cork layer in the plant.

• Composites Research
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• 제36권2호
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• pp.86-91
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• 2023

Thermoplastic polyurethane (TPU) is a material whose mechanical properties change according to the phase separation of its unique internal microstructure and is therefore used in various industries. Use of TPU as composites helps in improving the desirable characteristics and properties in accordance with usage. Eco-friendly fillers one of the fillers are on the rise and those are mostly used for reinforcing role. Suberin, which can be extracted from cork, is the main component of cork. It is known to serve high damping property of elastomer composite. The original chemical structure of Suberin is an aliphatic polyester aggregate. In this research, Suberin is obtained after depolymerization into an oligomer having 2 or 3 ester bonds through alkaline hydrolysis. The extracted suberin was added to the matrix which is thermoplastic polyurethane as an eco-friendly filler for improving vibration damping property. As a result, when 10 wt% of suberin was added into thermoplastic polyurethane the existing trade-off relationship was overcome. And it is attained the elastic modulus and damping factor at room temperature improving 92 and 59%, respectively, compared to the original matrix. Those results are from the interaction between the microstructure of TPU and suberin.

• 한국의상디자인학회지
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• 제19권1호
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• pp.135-145
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• 2017

In order to analysis on color difference of yellow natural dyes, I have dyed cellulose and protein fabrics. The results of experiment have been analysed by wavelength of maximum absorption, amounts of dye uptake, color difference, Hunter's value and Munsell's value. The results from these analyses are as follows : Bud of pagoda tree, Amur cork, and Curcuma showed greenish yellow color, Gardenia Jasminoides showed reddish yellow color. Barberry root showed reddish yellow color with post-mordanting method on cellulose fabric. Moreover, Dupioni silk was dyed in reddish yellow color by Barberry root and Rhubarb. In addition to Chroma index, Gardenia Jasminoides and Curcuma showed clear color overall. However, dyeing rayon and silk by Barberry root, and dyeing silk by Rhubarb showed clear color. Comparing all the results to actual dyed materials, Bud of pagoda tree had small dye uptake, and both ${\Delta}a$ and ${\Delta}b$ value were short which can't recognized the yellow color easily. Dye uptake of Amur cork and Gardenia Jasminoides was small just like Bud of pagoda tree. However, ${\Delta}b$ value order was Gardenia Jasminoides>Amur cork>Bud of pagoda tree. Therefore, Gardenia Jasminoides recognized reddish yellow because of big value of red color and yellow color. In case of Barberry root and Rhubarb which have larger dye uptake, Baberry root recognized yellow color on rayon only, and couldn't recognized yellow color on bleached cotton fabric, ramie, silk, and dupioni silk. Rhubarb recognized yellow color on rayon with pre-mordanting method only, but recognized silk and dupioni silk as brown like color. Moreover, we could not analyze color by dye uptake, Lab, and H(v/c) for Barberry root and Rhubarb. As a result, I think we need to attach color table for the research paper which handled the color of dyeing materials.

• Structural Engineering and Mechanics
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• 제64권5호
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• pp.543-555
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• 2017

The non-linear behaviour of integral infilled frames (in which the infill and the frame are bonded together with help of various interface materials) is studied both experimentally and numerically. The experiments were carried out on one-sixth scale two-bay and three-storey reinforced concrete frames with and without infill against static cyclic loading. Three interface materials - cement mortar, cork and foam have been used in between the infill and the frame. The infill, interface and the frame are bonded together is called integral frame. The linear and non-linear behaviors of two dimensional bare frame and integral infilled frame have been studied numerically using the commercial finite element software SAP 2000. Linear finite element analysis has been carried out to quantify the effect of various interface materials on the infilled frames with various combinations of 21 cases and the results compared. The modified configuration that used all three interface materials offered better resistance above others. Therefore, the experiments were limited to this modified infilled frame case configuration, in addition to conventional (A1-integral infilled frame with cement mortar as interface) and bare frame (A0-No infill). The results have been compared with the numerical results done initially. It is found that stiffness of bare frame increased by infilling and the strength of modified frame increased by 20% compare to bare frame. The ductility ratio of modified infilled frame was 42% more than that of the conventional infilled frame. In general, the numerical result was found to be in good agreement with experimental results for initial crack load, ultimate load and deformed pattern of infill.

• 대한방사선치료학회지
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• 제25권2호
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• pp.137-143
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• 2013

목 적: 불균질부를 포함하고 있는 치료부위의 치료계획 시 불균질 경계면에서의 TPS상 선량분포와 phantom을 이용하여 측정된 실제 선량분포를 비교하여 그 차이를 알아보고자 한다. 대상 및 방법: 4 cm 두께의 solid water phantom 사이에 폐와 유사한 밀도를 가진 8 cm 두께의 cork (density: 0.23 $g/cm^2$)를 위치시켜 phantom을 제작하여 CT 영상을 획득하였으며, 본원에서 사용하고 있는 Pinnacle 치료계획 시스템의 Collapsed-cone(CC) convolution 선량계산 알고리즘을 이용하여 6/15 MV 광자선으로 치료 계획된 선량분포와 실제 phantom에 EBT2 필름을 삽입해 측정한 선량을 비교 평가하였다. 또한 실제 폐암 환자와 유사한 치료계획을 비교하기 위해 Phantom 내부에 치료하고자 하는 종양부위(target volume)로 가정한 파라핀($3{\times}3{\times}3$ cm)을 Location "A" (일반조직과 떨어져있는 가상의 종양: 섬모델)와 Location "B" (일반조직과 붙어있는 가상의 종양: 반도모델)에 삽입하여 CT scan 후 치료계획을 시행하였다. 선량계획과 동일한 조건으로 Phantom을 set-up 후 Phantom의 paraffin target volume 경계면 A (Ant방향), B (Rt방향), C (Post 방향) point에 필름을 삽입하고 방사선을 조사하여 측정된 선량을 TPS선량과 비교평가 하였다. 결 과: 불균질 phantom을 이용한 계획선량과 측정선량과의 차이는 solid water와 cork 경계면을 제외한 부분에서 선량차이가 크지 않았지만 밀도가 급격히 변화하는 첫 번째 구간과 두 번째 구간에서 -5.4%~-12.6%의 선량감소를 보였다. 또한 paraffin target을 삽입한 실험에서는 Location "A"의 경우 실제 측정선량이 A, B, C point에서 각각 -2.5~-4.7%, -2.3~-2.8%, -4.5~-8.8%의 낮은 선량을 나타냈으며, Location "B"의 경우에도 A, B, C point에서 각각 0.08~5.27%, -3.17~-4.74%, -7.86~-11.56%의 선량 차이를 나타내었다. 결 론: 이번 연구의 결과 불균질부 내에서의 치료계획 시스템의 계획된 선량과 실제 측정된 선량에 오차의 가능성이 확인되었다. 급속도로 발전하고 있는 방사선 치료기술과 그만큼 정밀함을 요하는 치료계획 시 이러한 가능성에 대해 인지하고 선량검증에 대한 여러 방법들을 연구하고 개발하는 것이 치료의 발전과 필수적으로 동반되어야 할 것이며 본원에서도 이번 연구를 통해 치료계획 시 발생할 수 있는 변수에 대해서 더 주의 깊게 판단하고 적용할 수 있을 것으로 사료된다.

• 한국가구학회지
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• 제23권1호
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• pp.1-9
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• 2012

Sustainable furniture designs are expressed through reutilization, reuse or redesign of the whole of part of natural materials and existing products. These designs contain natural emotions and show those propensities such as uncertainty, integrity, essentiality and experimental natures. Designs that use natural materials such as wood, bamboo, cork, plants, stones and water have sufficient beauty in themselves and thus these materials are not specially processed but their essence is pursued in those designs. Of those materials, the natural material water is used to pursue the essence of aqua while presenting a new furniture design through an experimental method. The circularity of aqua shares its meaning with the circularity of sustainable designs. In addition, the liquidity of aqua will be grafted onto IT technology to express variable shapes in order to present a new direction of furniture designs.

• The Journal of Advanced Prosthodontics
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• 제7권1호
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• pp.39-46
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• 2015

PURPOSE. The mechanical and interfacial characterization of laser welded Co-Cr alloy with two different joint designs. MATERIALS AND METHODS. Dumbbell cast specimens (n=30) were divided into 3 groups (R, I, K, n=10). Group R consisted of intact specimens, group I of specimens sectioned with a straight cut, and group K of specimens with a $45^{\circ}$ bevel made at the one welding edge. The microstructure and the elemental distributions of alloy and welding regions were examined by an SEM/EDX analysis and then specimens were loaded in tension up to fracture. The tensile strength (TS) and elongation (${\varepsilon}$) were determined and statistically compared among groups employing 1-way ANOVA, SNK multiple comparison test (${\alpha}$=.05) and Weibull analysis where Weibull modulus m and characteristic strength ${\sigma}_0$ were identified. Fractured surfaces were imaged by a SEM. RESULTS. SEM/EDX analysis showed that cast alloy consists of two phases with differences in mean atomic number contrast, while no mean atomic number was identified for welded regions. EDX analysis revealed an increased Cr and Mo content at the alloy-joint interface. All mechanical properties of group I (TS, ${\varepsilon}$, m and ${\sigma}_0$) were found inferior to R while group K showed intermediated values without significant differences to R and I, apart from elongation with group R. The fractured surfaces of all groups showed extensive dendritic pattern although with a finer structure in the case of welded groups. CONCLUSION. The K shape joint configuration should be preferred over the I, as it demonstrates improved mechanical strength and survival probability.

• Smart Structures and Systems
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• 제21권3호
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• pp.287-303
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• 2018

Applications of energy harvesting from mechanical vibrations is becoming popular but the full potential of such applications is yet to be explored. This paper addresses this issue by considering an application of energy harvesting for the dual objective of serving as an indicator of structural health monitoring (SHM) and extent of control. Variation of harvested energy from an undamaged baseline is employed for this purpose and the concept is illustrated by implementing it for active vibrations of a pipe structure. Theoretical and experimental analyses are carried out to determine the energy harvesting potential from undamaged and damaged conditions. The use of energy harvesting as indicator for control is subsequently investigated, considering the effect of the introduction of a tuned mass damper (TMD). It is found that energy harvesting can be used for the detection and monitoring of the location and magnitude of damage occurring within a pipe structure. Additionally, the harvested energy acts as an indicator of the extent of reduction of vibration of pipes when a TMD is attached. This paper extends the range of applications of energy harvesting devices for the monitoring of built infrastructure and illustrates the vast potential of energy harvesters as smart sensors.