• The Korean Journal of Applied Statistics
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• v.31 no.3
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• pp.353-366
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• 2018

This study uses mixed-effects models to predict thigh soft tissue artefact (STA), relative movement of soft tissue such as skin to femur occurring during hip joint motions. The random effects in the model were defined as STA and the fixed effects in the model were considered as skeletal motion. Five male subjects without musculoskeletal disease were selected to perform various hip joint rotational motions. Linear mixed-effects models were applied to markers' position vectors acquired from non-invasive method, photogrammetry. Predicted random effects showed similar patterns of STA among subjects. Large magnitudes of STA appeared on the points near the hip joint regardless of sides; however, small values appeared on the distal anterior.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.7
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• pp.818-825
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• 2004

In this paper, the study of effects of flow parameters on flame structure and NOx emission concentration was performed in co-axial. laminar partially premixed methane/air flames. Such (low parameters as equivalence ratio(${\Phi}$), fuel split percentage($\sigma$), and mixing distance(x/D$\_$i/) were defined as a premixing degree and varied within ${\Phi}$=1.36∼9.52, $\sigma$=50∼100, and x/D$\_$i/=5∼20. The image of OH$\^$*/ and NOx concentration were obtained with an ICCD camera and a NOx analyzer. The flame structure observations show a categorization of partially premixed flames into three distinct flame regimes corresponding to ${\Phi}$<1.7(premixed flame structure), 1.7<${\Phi}$<3.3(hybrid structure), and ${\Phi}$>3.3(diffusion flame structure existing a luminous sooting region) at $\sigma$=75%, and x/D$\_$i/=10. As o decreases from 100% to 50%, and x/D$\_$i/ decreases, nonpremixed flame structure appear at low equivalence ratio relatively. In addition, the measured emissions for NOx rise steeply from ${\Phi}$=1.7, to ${\Phi}$=3.3, then constants ${\Phi}$>4.76. NOx emissions decrease with increase the level of premixing level. In conclusion, the main effect on flame structure and NOx production was at first equivalence ratio(${\Phi}$), and next fuel split percentage($\sigma$), and finally mixing distance(x/D$\_$i/).

• Elastomers and Composites
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• v.11 no.1
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• pp.63-73
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• 1976

에너지 위기후(危機後) 천연자원(天然資源)이 점차로 고갈(枯渴)되여 가고 있는 요즈음 고무산업(産業)에도 이의 여파(餘波)로 몇가지 영향(影響)을 받고 있다. 한 예(例)로 일반적(一般的)으로 널리 사용(使用)되고 있는 23.5% 스티렌 함량(含量)의 SBR제조(製造)에 있어 값싼 부타디엔 및 스티렌 단량체(單量體)를 만들기에는 세계적(世界的) 자원부족(資源不足)으로 인(因)하여 심각(深刻)한 위치(位置)에 놓여있어 장차(長次) 안가(安價)이며 충분(充分)한 량(量)의 합성(合成)고무를 공급(供給)하기에는 SBR과 다른 고무와의 부분적(部分的) 또는 완전(完全)히 다른 합성(合成)고무로 대치 사용함이 타당(妥當)할 것이다. 확범위(擴範圍)한 실험(實驗)끝에 $50\sim55%$ vinyl함량(含量)의 폴리부타디엔 고무가 제조(製造)되였는데 이것은, 자동차용 트레드 부분과 wet skid resistance애 많이 이용(利用)되고 있는 유화(乳化) 또는 용액중합(溶液重合)의 SBR과 매우 유사한 물리적(物理的) 특성(特性)을 나타낸다. 그리고 $45\sim50%$ vinyl함량 폴리부타디엔 고무는 오히려 SBR보다 내마모와 crack growth가 더 좋음을 알았다. 45% vinyl함량 폴리부타디엔 고무와 SBR, cis-플리부타디엔 고무(30/35/35)의 3성분(成分) 혼합체(混合體)는 65/35비율(比率)의 SBR/cis-폴리부타디엔 고무보다 트레드의 마모성이나 미끄럼성이 더 좋았으며 또한 45/20/35 비율(比率)의 혼합체(混合體)도 역시 내 마모성이 좋은 것으로 나타났다. 이와같은 medium vinyl 폴리부타디엔 고무는 SBR로 이용(利用)되고있는 (非)타이어 산어(産業)에서도 SBR대신 단독(單獨) 또는 일부분(一部分) SBR과 혼합(混合)해서 사용(使用)할 수 있다. medium vinyl폴리부타디엔 고무는 낮은 발열성(發熱性)(heat build-up) 그리고 내(耐)빵구성(性)이 우수(優秀)하며 SBR과 유사(類似)한 물리적(物理的) 특성(特性)을 가지고 있으므로 스티렌의 생산(生産)이 활발(活發)해지고 값이 저겸(低謙)하드라도 위와같은 장점(長點) 때문에 장차(長次) 계속 사용(使用)될 것이며 더욱더 개발(開發)될 것이다.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.11
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• pp.769-775
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• 2013

UV-induced transformations in the characteristics of dissolved organic matter (DOM) and the subsequent effects on the disinfection by-product formation potential (DBPFP) were investigated using the mixtures of the two humic substances with different sources, and two different size fractions of Suwannee River fulvic acid (SRFA). 7 day-photodegradation resulted in the decrease of specific ultraviolet absorbance (SUVA) of the mixtures as well as the specific DBPFP. After the irradiation, however, higher specific DBPFP values were consistently observed at the same range of the SUVA values. This suggests that non UV-absorbing components, generated by the UV-irradiation, may contribute to the formation of DBPs. Two different molecular size fractions of SRFA showed dissimilar responses to photodegradation. The behavior was also influenced by the types of the DBPs generated. Higher levels of trihalomethenes (THMs) were formed per organic carbon for the high molecular fraction compared to the low molecular fraction, whereas no differences were found in the formation of haloacetic acids (HAAs) between the two different size fractions. The formation of the two types of DBPs also differed by the irradiation times. Specific formation potential of THMs consistently increased upon the irradiation, whereas HAAs showed the initial increase followed by the decrease in their specific formation potential.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.1
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• pp.8-12
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• 2015

Non-esterified bio-diesel fuel saves cost by no esterified process and its performance was more similar to diesel oil than esterified bio-diesel fuel when the fuel blended 95% diesel oil and 5% it was used on diesel engine with electronic control system. A performance optimization is necessary for application of non-esterified bio-diesel fuel blended with diesel oil 95% on the latest diesel engine. In this study, test using fractional factorial design was accomplished at 25% and 50% partial load in order to evaluate influence of controllable 6 factors on responses such as specific fuel consumption, nitrogen oxides and coefficiency of variation of indicated mean effective pressure as basic experiment for performance optimization of this fuel. It is cleared that the injection timing and common rail pressure of 6 factors are mainly effective and its effect level is different according to load.

• Fire Science and Engineering
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• v.20 no.4 s.64
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• pp.58-64
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• 2006

Smoke extraction in tunnel fire is investigated experimently with thermal model. The object is a immersed tunnel, of which the partial extraction system exists between the tubes. The model tunnel is measured 12 m long, 0.5 m wide and 0.35 m high. The fire is simulated to pool fire and the size corresponds to full scale fire of 5 MW based on Froude modeling. The performance of partial extraction system is determined under two ventilations, natural and longitudinal ones. The results show that compared with longitudinal ventilation, the smoke extraction efficiency of natural ventilation is increased about 30% because of smoke stratification in tunnel. Also the efficiency is identical to the iso-thermal model. The results will be help for activation of the ventilation system in emergency such as in the event of tunnel fires.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.12
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• pp.1924-1934
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• 2009

Mixture phenomena are present in the overall culture due to internationalization in a modern society. A unique feel is required in materials due to the increasing demand for knit wear and there is a need for a strategic plan to achieve this. This study analyzed the appearance frequency and expressive characteristics of mixture phenomena based on selected data from collections related to the mixture phenomena trends in modern women's fashion from 2000 to 2008. Among the mixture phenomena, the mixture of the high and low class cultures had the highest frequency of occurrence and was expressed most often since the expansion of design areas was due to vague high and low concepts. The mixture of sexes showed the sharing of knit wear trends between the sexes with the pursuit of functionality. The mixture of styles showed a tendency to increase since the traditional form was transformed into a mixture of typical styles. The mixture of spaces showed a mixture of old and traditional knit wear patterns from Northern Europe and modern elements. The mixture of other materials showed the partial preceding mixture and the decorative materials that existed beyond it. The mixture of functions refers to the used characteristics of the two items. Imagination will grow and increase the possibility of expressions with the mixture of the other areas.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1610-1611
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• 2011

실선로 전력 케이블의 부분방전 측정은 주위 전력설비의 신호들이 혼합되면 정확한 부분방전 진단이 어려운 면이 있다. 본 논문에서는 15kV급 EPR 난연 케이블을 대상으로 거리에 따른 부분방전 신호를 검출 및 감쇄 정도 확인 시험을 통하여 발생 위치 추정 기준을 마련하고자 한다. 이를 위해 길이 500m의 EPR 난연 케이블을 제작하여 모의 선로를 구성하였고, IEC60270에 적합한 Calibrator를 이용하여 신호를 인가한 후 HFCT 센서를 사용하여 일정한 거리를 두고 방전 신호를 검출하고, Techimp사(社)의 PDBASE와 OMICRON사(社)의 MPD600을 이용하여 부분방전 신호를 분류하였다. 전압 인가 지점에서 단계적인 거리증가에 따른 부분방전 신호 감쇄 현상 및 일정 길이(300[m])에 대한 주입 신호별 감도 측정을 분석하였다. 본 논문의 시험대상인 15kV급 EPR 난연 케이블은 원자력 발전소의 배전선으로 사용하기 위해 제작된 것으로, 포설 후 절연체 내에 B/D가 발생했다고 가정했을 때, PD신호의 검출 및 대략적인 위치의 추정은 안전을 최우선시 하는 원자력 발전 및 배전 부문에서 주요한 문제로 부각 될 것이다.

• Journal of the Korean Society of Propulsion Engineers
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• v.9 no.3
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• pp.10-17
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• 2005

A performance prediction model is developed for partially admitted axial-type turbines. Losses generated within the turbine are classified to the windage loss, expansion loss and mixing loss. The developed loss model is compared with an experimental result. The results predicted with the developed model agree well with the experimental results than those predicted with several other models because this model considers three different kinds of losses. Moreover, this model predicts well the performance even the partial admission is changed. So, this model could be applied to predict the performance of partially admitted axial turbine and it has a high accurate performance.

• Journal of the Korean Institute of Gas
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• v.14 no.1
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• pp.8-14
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• 2010

In this study, we experimentally investigated a compression ignition engine operated with Bio-diesel blended LPG fuel. In particular, the performance, emissions characteristics (including total hydrocarbon, carbon monoxide, nitrogen oxides, and carbon dioxides emissions), and combustion stability of a CI engine fueled with Bio-diesel blended LPG fuel were examined at 1500 rpm. The percentage of Bio-diesel in the fuel blend ranged from 20-60%. The results showed that stable engine operation was possible for a wide range of engine loads up to 40% Bio-diesel by mass. When the Bio-diesel content was increased, leading to a decrease in the lower heating value of the blended fuel, the cetane value increased, resulting in a advanced start of heat release. Exhaust emission measurements showed that THC and CO emissions were increased when using the blended fuel at low engine speeds due to partial burn from over-mixing. NOx emission was emitted less at lower loads and more at higher loads.