• Composites Research
• /
• 제36권3호
• /
• pp.173-179
• /
• 2023

The sandwich structure, consisting of a core and a face sheet, is used for lightweight structural application. Generally, cellular structures like honeycomb, foam, and lattice structures are utilized for the core. Among these, lattice structures have several advantages over other types of structures. In other studies, curved lattice structures were reported to have higher mechanical properties than straight structures by converting shear stresses acting on the structure into compressive stresses. Moreover, the addition of vertical struts can have a positive effect on the mechanical properties of the lattice structure. For the purpose, two lattice structures with Circle Arch (CC) and Circular Arch with a vertical column (CC_C) were studied, which were fabricated by using selective laser sintering was conducted. The result showed that CC_C has dramatic performance improvements in specific strength, modulus, and strain energy density compared to CC, confirming that vertical struts played a significant role in the lattice core. Finite element analysis was employed to determine the cause of the stress behavior of CC and CC_C. This study is expected to help design structurally superior lattice cores and sandwich structures.

• 한국해양공학회지
• /
• 제37권5호
• /
• pp.198-204
• /
• 2023

In response to the complexity and time demands of conventional methods for estimating the hydrodynamic coefficients, this study aims to revolutionize ship maneuvering analysis by utilizing automatic identification system (AIS) data and the Support Vector Regression (SVR) algorithm. The AIS data were collected and processed to remove outliers and impute missing values. The rate of turn (ROT), speed over ground (SOG), course over ground (COG) and heading (HDG) in AIS data were used to calculate the rudder angle and ship velocity components, which were then used as training data for a regression model. The accuracy and efficiency of the algorithm were validated by comparing SVR-based estimated hydrodynamic coefficients and the original hydrodynamic coefficients of the Mariner class vessel. The validated SVR algorithm was then applied to estimate the hydrodynamic coefficients for real ships using AIS data. The turning circle test wassimulated from calculated hydrodynamic coefficients and compared with the AIS data. The research results demonstrate the effectiveness of the SVR model in accurately estimating the hydrodynamic coefficients from the AIS data. In conclusion, this study proposes the viability of employing SVR model and AIS data for accurately estimating the hydrodynamic coefficients. It offers a practical approach to ship maneuvering prediction and control in the maritime industry.

• Advances in nano research
• /
• 제16권1호
• /
• pp.53-69
• /
• 2024

Advancements in the technology of building materials has led to diverse applications of nanomaterials with the aim to monitor concrete structures. While there are myriad instances of the use of nanoparticles in building materials, the production of smart nano cement-composites is often expensive. Thereupon, this research aims to discover a sustainable nanomaterial from tyre waste using the pyrolysis process as part of the green manufacturing circle. Here, Nano Structure Tyre-Char (NSTC) is introduced as a zero-dimension carbon-based nanoparticle. The NSTC particles were characterized using various standard characterization techniques. Several salient results for the NSTC particles were obtained using microscopic and spectroscopic techniques. The size of the particles as well as that of the agglomerates were reduced significantly using the milling process and the results were validated through a scanning electron microscope. The crystallite size and crystallinity were found to be ~35nm and 10.42%, respectively. The direct bandgap value of 5.93eV and good optical conductivity at 786 nm were obtained from the ultra violet visible spectroscopy measurements. The thermal analysis reveals the presence of a substantial amount of carbon, the rate of maximum weight loss, and the two stages of phase transformation. The FT-Raman confirms the presence of carboxyl groups and a ID/IG ratio of 0.83. Water contact angle around 140° on the surface implies the highly hydrophobic nature of the material and its low surface energy. This characteristic process assists to obtain a sustainable nanomaterial from waste tyres, contributing to the development of a smart building material.

• 대순사상논총
• /
• 제33집
• /
• pp.31-62
• /
• 2019

본 연구는 무극과 태극 상관연동의 대순우주론에 관한 연구를 목적으로 한다. 대순우주론은 구천상제께서 세상에 펼친 대순에 근거하여 이루어진 우주론이다. 이 글에서는 대순우주론이 구천상제의 무극초월, 도주정산의 태극내재, 무극과 태극 상관연동의 후천개벽의 삼단계로 전개되고 있음을 밝히고자 한다. 먼저 구천상제의 무극초월은 생장염장과 무위이화로 드러난다. '생장염장(生長斂藏)'의 사의(四義)는 우주순환 원리를 표상하며, 무위이화는 그 성품을 바르게 하고 기운을 올곧게 함은 꾸밈이 없이 성취함을 일컫는다. 이는 상생진법의 정음정양에 근거하여 이루어진다고 말할 수 있다. 또한 도주정산의 태극내재는 만물생장과 생성변화로 이루어진다. 만물생장은 세상의 모든 것들이 저마다 생명을 틔워 생장하면서 각각 생애 절정을 향해 빛내려고 하는 특징을 드러낸다고 할 것이다. 아울러 뇌성보화의 지배자양에 의해 선천의 상극기운과 습관을 버리고, 음양이기(陰陽二氣)를 결합하여 동정진퇴(動靜進退)의 내재변화(內在變化)로 천기(天氣)와 지기(地氣)를 승강(昇降)하게 한다. 그리고 무극과 태극 상관연동의 후천개벽은 무극초월과 태극내재 상관연동의 대순일원으로 일상에서 도를 체화하는 단계로서 켄 윌버의 통합모델과 상통한다. '도통진경(道通眞境)'은 참된 도를 체화하는 경지이고, '도지통명(道之通明)'은 도를 밝혀 후천개벽의 새 세상을 전개함을 의미한다. 선녀들이 음악을 연주하고, 불로초가 피어나고, 학들이 노니는 안온하고 평화로운 모습이다. 인간은 지상신선이 되고, 후천개벽의 실화기제가 되어 마침내 시공(時空)을 넘나드는 대자유인으로서 행복결실을 맺는 형상이다. 대순사상은 대순진리의 사상으로 도주께서 50년간 각고의 고초를 겪으시며 '태극내재'를 새 밝힘으로 함으로 진법(眞法)을 완성시킨 것에 근거한다. 도주께서 1958년, 도전께 종통을 물려주시면서 도의 전반을 맡아가도록 하명함으로 대순사상은 도전에 의해 대순사상으로 계승되었다. 또한 도전께서 '대순(大巡)'을 크게 순찰하는 의미로 새겨서, 구천상제의 삼계대순(三界大巡) 개벽공사(開闢公事) 뜻을 담보했다. 아울러 '대순(大巡)이 원(圓)으로, 무극과 태극의 상관연동 우주론을 나타내고 있다고 새 밝힘 하였다. 결국 대순사상 우주론은 대순사상의 심층차원을 이해할 수 있게 하면서, 무극초월과 태극내재 상관연동으로 대순일원의 정체성을 드러내고 있음을 새 밝힘 할 수 있다. 대순우주론은 대순일원으로서 생활실천으로 원융회통 성격을 제시한다. 본 연구에서는 문헌학의 진정성과 해석학의 합당성을 활용하여, 대순우주론의 무극과 태극 상관연동의 공공작용을 규명하게 된다. 다양·다중·다층 해석학으로 후천개벽의 생활실화에 접근함으로, 후천개벽의 실천담론을 실화기제로 밝히고자 한다. 대순사상 미래전망은 무극초월과 태극내재 상관연동으로 대순의 '일원회통(一圓會通)' 원만구족으로 생명살림에 관건이 있다고 할 것이다.

• 한국의류학회지
• /
• 제41권5호
• /
• pp.783-795
• /
• 2017

This study measured consumer's recognition, reliability, emotion and images about current eco-marks as well proposed an eco-mark rating scale and mark designs to improve consumer's trust on the fashion product marks. We used a questionnaire survey to collect data from 150 persons about knowledge, interests, and practice on eco fashion products in relation to trustfulness and positive images for three domestic and three international eco-marks. We evaluated and gave eco scores to six fiber-type products (cotton, organic cotton, wool, polyester, biodegradable polyester and nylon) in terms of consumer's use, water & land consumption, waste amount, carbon footprint, and toxicity. We suggested a new 5-level rating scale for eco marks, which quantified the concept of environmental friendliness of fiber products. The design for eco-mark of rating scale showed the total grade with two sub scores of environmental sides and human sides developed with an improved visual understanding for consumers. The design is one through benchmarking the energy-consumption efficiency mark, which is familiar to consumers such as a half circle shape to save environment resources to alarm consumers to environment problems.

• 한국태양에너지학회 논문집
• /
• 제28권3호
• /
• pp.7-14
• /
• 2008

400RT geothermal system which is the biggest capacity among on-operations at present in Korea is measured and evaluated on 23rd${\sim}$26th Jan. 2008 during those days building is not allowed owners and/or tenants to move in. The geothermal system is consist with vertical-typed 112 geothermal heat exchangers which are installed circle-like 1 row with 4m interval, and has 16 units of 25USRT geothermal-source heat pump(GSHP)s. And each 5 units of circulation pump are running for geothermal heat exchangers and hot water supplies. The followings are the results. The temperatures at G.L. -70m of 2 boreholes are varied quite similarly. The average temperature difference between inlet and outlet of geothermal pipes is $4.1^{\circ}C$, and that of hot water supply is $3.2^{\circ}C$, of Zone 3's each 4 GSHPs when being operated. Despite temperature fluctuations by heating loads, the average temperature difference between main pipes of inlet and outlet of geothermal heat exchangers is measured as $4.1^{\circ}C$. This study propose "Geothermal System COP" which includes not only consumed electric power by compressor but also circulation pumps and auxiliary utilities. By comparing the geothermal system COP with GSHP's performance specification, it is clear that the performances of GHSPs of this site are satisfied with the specification.

• 한국해양공학회지
• /
• 제31권2호
• /
• pp.81-90
• /
• 2017

The 1MW OTEC (Ocean Thermal Energy Conversion) platform was designed for application in equatorial seas. In this study, the OTEC platform was investigated using numerical and experimental methods. An octagon-shaped OTEC platform was investigated using the Ocean Engineering Basin of KRISO. These experiments included various tests of regular waves, irregular waves and irregular waves with current (wave+current). The responses of the platform in regular waves showed good agreement between the numerical and experimental results, including the motion RAO, wave run up, and mean drift force. The peak period of heave and pitch motions were observed around 0.5 rad/s, and the effect of the total reflection was found under short wave conditions. The standard deviation (STD) of the platform motion was checked in irregular waves of equatorial and Hawaiian seas. The STD of the pitch was less than $4^{\circ}$ different from the operability requirement under equatorial conditions and the surge STD of the wave frequency showed good agreement between the numerical and experimental results. The STD values of the surge and pitch were increased 66.6% and 92.8% by the current effects in irregular waves, but the pitch STD was less than $4^{\circ}$ under equatorial conditions. This study showed that the STD of the surge was affected by spring effects. Thus, the watch circle of the platform and tension of the mooring lines must be evaluated for a specific design in the future.

• 한국지반신소재학회논문집
• /
• 제21권4호
• /
• pp.31-40
• /
• 2022

최근 건설시장의 다각화와 미래 에너지 자원개발이라는 관점에서 미개발된 에너지 자원(석유, 천연가스 등)이 대량으로 매장되어 있는 극한지(북극권) 개발 사업이 활발히 추진되고 있다. 이러한 지역에서는 극한의 기후로 인한 동토 지반의 침하나 동상 등의 문제가 항상 발생하기 때문에 지반 구조물의 안정성 확보를 위해 열적 특성 분석이 반드시 필요하다. 본 논문에서는 동토 지역에서 지반동결과 관련된 문제들을 평가하고 기술적으로 해결하기 위한 기초 자료 제공을 목적으로, 캐나다 앨버타주 오일샌드 매장 지역의 동토 시료에 대한 열적 특성을 국내 시료와 비교·분석하였다. 일련의 실내 실험을 통해 동결온도에 대한 시간에 따른 부동 수분량을 측정하여 흙의 종류와 동결온도가 부동 수분량에 미치는 영향에 대하여 고찰하였고, 토양의 잠열, 열용량 및 열전도도를 정확하게 파악하기 위하여 동결/비동결 조건에 대한 열전도도 실내 실험을 수행하였다. 실험결과, 동결 완료 후 온도별로 상이한 부동 수분량과 열전도도 특성은 동토 지역 동결온도가 동토의 역학 거동에 영향을 끼칠 수 있음을 규명하였다.

• Korean Journal of Acupuncture
• /
• 제21권4호
• /
• pp.1-19
• /
• 2004

Objectives : To understanding biological mechanism of acupuncture therapy, we have proposed a hypothesis. First of all, there exists electric property in meridian and meridian point. Second of all, energy flowing in meridian is related with electric property. Third of all, there is electronic interaction between the operator who performs acupuncture therapy and the receiver who is given acupuncture therapy. Forth of all, acupuncture effects may depend on the electric capacity which is transferred between the operator and the receiver via acupuncture needle. Methods : Under the hypothesis, we studied the effects of electric change in $ST_{37}(+)\;and\;ST_{39}(-)$ generated by Tanchim (彈鍼) manipulation which was stimulated at $ST_{36}$ point. And compared with data on the changes of electric change from the hand of the operator during acupuncture stimulation. Electric charge induced via acupuncture needle from the operator may be important factor that causes the changes of electric change in meridian and acupoint in the receiver. Therefore we investigated the changes of electric charge induced by the operator using Maclab 400 by the following methods. The one was in stable electric circle condition and the other was in unstable electric circle condition. Results : In this experiments, the changes of electric change from the stimulation type of Tanchim manipulation performed in our lab condition in acupuncture therapy was induced at least three factor, one was the difference of bio-potentials between the operator and the receiver of acupuncture therapy, another was the depth of acupuncture insertion from the skin of the receiver, the other was an electromyogram of the receiver. Conclusion : The data imply that the first factor should make a capacitance current when the operator touched the acupuncture needle which was inserted in the receiver. Therefore, the results suggest that capacitance currents stimulus in electronic view may be important factor in acupuncture therapy between the operator and the receiver of acupuncture therapy.

• Korean Journal of Acupuncture
• /
• 제22권4호
• /
• pp.9-27
• /
• 2005

Objective : hypothesis. First of all, there exists electric property in meridian and meridian point. Second of all, energy flowing in meridian is related with electric property. Third of all, there is electronic interaction between the operator who performs acupuncture therapy and the receiver who is given acupuncture therapy. Forth of all, acupuncture effects may depend on the electric capacity which is transferred between the operator and the receiver via acupuncture needle. Methods : Under the hypothesis, I studied the effects of electric charge in ST37(+) and ST39(-) generated by Apchim (押鍼) manipulation which was stimulated at ST36 point. And compared with data on the changes of electric charge from the hand of the operator during acupuncture stimulation. Electric charge induced via acupuncture needle from the operator may be important factor that causes the changes of electric charge in meridian and acupoint in the receiver. Therefore we investigated the changes of electric charge induced by the operator using Maclab 400 by the following methods. The one was in stable electric circle condition and the other was in unstable electric circle condition. In this experiments, the changes of electric charge from the stimulation type of Apchim manipulation performed in our lab condition in acupuncture therapy was induced at least three factor, one was the difference of bio-potentials between the operator and the receiver of acupuncture therapy, another was the depth of acupuncture insertion from the skin of the receiver the other was an electromyogram of the receiver. Results :The data imply that the first factor should make a capacitance current when the operator touched the acupuncture needle which was inserted in the receiver. Therefore, the results suggest that capacitance currents stimulus in electronic view may be important factor in acupuncture therapy between the operator and the receiver of acupuncture therapy.