• 오토저널
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• 제4권2호
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• pp.47-57
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• 1982

Smoke, Hydrocarbon and Garbon Monoxide emissions of concern in environmental pollution on AVDS-170-2D diesel engine were studied experimentally and past studies on emissions of diesel engine were investigate. Engine speed and load were considered as variable factors influencing the emissions. The test results of a multicylinder, direct injection and turblcharged 4 cycle diesel engine were compared with past studies. Both emission levels of experimental study and past studies were markedly influenced by engine operation factors. The results obtained in this study can be summarized as follows; 1) Smoke intensity is proportional to engine load and varies with engine speed. 2) Hydrocarbon and nitric oxides emissions vary with engine speed and load. 3) Garbon monoxide emission is insensitive to engine speed and varies with engine load.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.723-732
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• 2020

A theoretical calculation model for ship stern bearings with large hull deformation is established and validated theoretically and experimentally. A hull simulation model is established to calculate hull deformations corresponding to the reaction force of stern bearings under multi-factor and multi-operating conditions. The results show that in the condition of wave load, hull deformation shows randomness; the aft stern tube bearing load obeys the Gaussian distribution and its value increases significantly compared with the load under static, and the probability of aft stern tube bearing load greater than 1 is 65.7%. The influence laws and levels between hull deformation and bearing reaction force are revealed, and suggestions for ship stern bearing specifications are proffered accordingly.

• 한국항만경제학회지
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• 제22권1호
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• pp.1-15
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• 2006

This paper analyzes how levels of logistics standardization are related to logistics costs. The study surveyed ratios of standard pallet use in order to measure levels of firms' standardization in logistics management. Research focused on how firms' logistics costs were related to their levels of logistics standardization and ratios of standard pallet use. After measuring use of standard pallets and logistics costs, optimal levels of logistics standardization were estimated based on survey data. Logistics costs and standardization were more related to labor than to freight volume or export. Results indicated that firms could reduce logistics costs by raising levels of logistics standardization; optimal levels of standard pallet use out of Korean firms' total manufacturing cargo volume were estimated at 44.26% for multi-standard pallets and 57.99% for a single standard pallet (a unit load system). The study demonstrated that adopting a single standard pallet results in better cost saving logistics systems than use of multi-standard pallet types. These results may explain why firms pursue standardization in logistics systems.

• Journal of Preventive Medicine and Public Health
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• 제49권3호
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• pp.153-164
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• 2016

Objectives: Previous studies have obtained conflicting findings regarding possible associations between indices measuring carbohydrate intake and dyslipidemia, which is an established risk factor of coronary heart disease. In the present study, we examined crosssectional associations between carbohydrate indices, including the dietary glycemic index (GI), glycemic load (GL), total amount of carbohydrates, and the percentage of energy from carbohydrates, and a range of blood lipid parameters. Methods: This study included 1530 participants (554 men and 976 women) from 246 families within the Healthy Twin Study. We analyzed the associations using a generalized linear mixed model to control for familial relationships. Results: Levels of the Apo B were inversely associated with dietary GI, GL, and the amount of carbohydrate intake for men, but these relationships were not significant when fat-adjusted values of the carbohydrate indices were used. Triglyceride levels were positively associated with dietary GI and GL in women, and this pattern was more notable in overweight participants (body mass index [BMI] ${\geq}25kg/m^2$). However, total, low-density lipoprotein and high-density lipoprotein cholesterol levels were not significantly related with carbohydrate intake overall. Conclusions: Of the blood lipid parameters we investigated, only triglyceride levels were positively related with dietary carbohydrate indices among women participants in the Healthy Twin Study, with an interactive role observed for BMI. However, these associations were not observed in men, suggesting that the association between blood lipid levels and carbohydrate intake depends on the type of lipid, specific carbohydrate indices, gender, and BMI.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.290-297
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• 2002

This paper presents analysis results for the effect of power control strategies on the part load performance of gas turbine based power generation systems utilizing exhaust heat of the gas turbine such as cumbined cycle power plants and regenerative gas turbines. For the combined cycle, part load efficiency variations were compared among different single shaft gas turbines representing various technology levels. Power control strategies considered were fuel only control and IGV control. It has been observed that gas turbines with higher design performances exhibit superior part load performances. Improvement of part load efficiency by adopting air flow modulation was analyzed and it is concluded that since the average combined cycle performance is affected by the range of IGV control as well as its temperature control principle, a control strategy appropriate for the load characteristics of the individual plant should be adopted. For the regenerative gas turbine, it is likewise concluded that maintaining exhaust temperature as high as possible by air flow rate modulation is required to increase part load efficiency.

• 한국유체기계학회 논문집
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• 제6권3호
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• pp.28-35
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• 2003

This paper presents analysis results for the effect of power control strategies on the part load performance of gas turbine based power generation systems utilizing exhaust heat of the gas turbine such as combined cycle power plants and regenerative gas turbines. For the combined cycle, part load efficiency variations were compared among different single shaft gas turbines representing various technology levels. Power control strategies considered were fuel only control and IGV control. It has been observed that gas turbines with higher design performances exhibit superior part load performances. Improvement of part load efficiency of the combined cycle by adopting air flow modulation was analyzed and it was concluded that since the average combined cycle performance is affected by the range of IGV control as well as its temperature control principle, a control strategy appropriate for the load characteristics of the individual plant should be adopted. For the regenerative gas turbine, it is likewise concluded that maintaining exhaust temperature as high as possible by air flow rate modulation is required to increase part load efficiency.

• 대한전기학회논문지:전력기술부문A
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• 제48권5호
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• pp.508-516
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• 1999

This paper presents a method for constructing composite power system effective load duration curves(CMELDC) at load points by Monte Carlo method. The concept of effective load duration curves(ELDC) in power system planning is useful and important in both HLII. CMELDC can be obtained from convolution integral processing of the probability function of unsupplied power and the load duration curve at each load point. This concept is analogy to the ELEC in HLI. And, the reliability indices (LOLP, EDNS) for composite power system are evaluated using CMELDC. Differences in reliability levels between HLI and HLII come from considering with the uncertainty associated with the outages of the transmission system. It is expected that the CMELDC can be applied usefully to areas such as reliability evaluation, probabilistic production cost simulation and analytical outage cost assessment, etc. in HLII, DC load flow and Monte Carlo method are used for this study. The characteristics and effectiveness of thes methodology are illustrated by a case study of the IEEE RTS.

• 한국건축시공학회지
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• 제15권5호
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• pp.473-481
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• 2015

공동주택의 구조형식이 점차 기둥식 구조로 바뀌면서 비내력 경량벽체의 수요가 증가하고 있다. 경량벽체는 구조적 안전을 위해 소정의 내력을 확보할 필요가 있다. 본 연구에서는 경량벽체의 정적 수평하중저항성 및 내충격성 시험방법의 기초자료로서 활용하기 위해 인간이 벽체에 가하는 힘을 실험적으로 파악하였다. 정적하중을 가하는 동작으로는 양손 밀기, 어깨 밀기, 등 기대기, 한 손 기대기의 4종류를 설정하였다. 동적하중을 가하는 동작으로는 발뒤꿈치차기, 어깨 부딪치기, 주먹치기의 3종류를 설정하였다. 하중해석 장치의 하중판 강성은 20kN/cm, 4.7kN/cm, 2.2kN/cm의 3종류로 설정하였다. 정적하중 해석결과로부터, 동작별 최대하중비(Pmax/W)는 양손 밀기의 경우 1.17~1.25, 어깨 밀기의 경우 0.95~0.99, 등 기대기의 경우 0.16~0.18, 한 손 기대기의 경우 0.12~0.15인 것을 알 수 있었다. 또한 동적하중 해석결과로부터, 동작별 최대하중비(Pmax/W)의 상한 값은 발차기의 경우 약 10.07, 어깨 부딪치기의 경우 4.46, 주먹치기의 경우 약 5.58인 것을 알 수 있었다.

• 한국물환경학회지
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• 제29권3호
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• pp.400-408
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• 2013

Total phosphorus was set as a target indicator to prevent eutrophication and algae growth, etc., in three major rivers (Nakdong River, Geum River and Yeongsang/Seomjin River) for the second phase (2011 ~ 2015) in total maximum daily loads (TMDLs) system. However, total phosphorus management was restrictively introduced, i.e., upstream of the Lake Daechung, in the Geum River watershed. Total phosphorus concentration and trophic levels in downstream of the Lake Daechung (include Mangyeong and Dongjin rivers) were increased more than upstream. Therefore, it is necessary to expand total phosphorus management in all watersheds of the Geum River. If total phosphorus was managed in all area of the Geum River watershed, it is possible to decrease total phosphorus concentration and trophic levels, and solve the unbalanced water quality between up and downstream of the Lake Daechung.

• Journal of Power Electronics
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• 제16권4호
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• pp.1245-1255
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• 2016

The single resonant inverter is widely employed in typical inductive power transfer (IPT) systems to generate a high-frequency current in the primary side. However, the power capacity of a single resonant inverter is limited by the constraints of power electronic devices and the relevant cost. Consequently, IPT systems fail to meet high-power application requirements, such as those in rail applications. Total harmonic distortion (THD) may also violate the standard electromagnetic interference requirements with phase shift control under light load conditions. A power regulation approach with selective harmonic elimination is proposed on the basis of a parallel multi-inverter to upgrade the power levels of IPT systems and suppress THD under light load conditions by changing the output voltage pulse width and phase shift angle among parallel multi-inverters. The validity of the proposed control approach is verified by using a 1,412.3 W prototype system, which achieves a maximum transfer efficiency of 90.602%. Output power levels can be dramatically improved with the same semiconductor capacity, and distortion can be effectively suppressed under various load conditions.