• Transactions of the Korean Society of Automotive Engineers
• /
• v.5 no.2
• /
• pp.42-49
• /
• 1997

This experimental study was performed to find fuel property variations of the ultrasonic energy adding gasoline and improve the spray characteristics of the multipoint injector for EFI engine. The cause and effect of the characteristic improvement of the ultrasonic energy adding fuel was found out by the chemical structure analysis (NMR, IR), distillation and viscosity test. The results are obtained that the chemical property of gasoline organizition was changed aromatics to paraffins and branch index as the physical characteristics of gasoline were improved by ultrasonic energy. There were higher distillation and lower viscosity in ultrasonic energy adding gasoline.

• Journal of Wind Energy
• /
• v.14 no.4
• /
• pp.43-49
• /
• 2023

We have studied biofouling in Korea's offshore wind farms by using image analysis through monitoring and surface energy analysis. To observe the biofouling characteristics, samples were fabricated using Micron extra 2 and PropOne, which have a self-polishing property, and Hempathane HS 55610, which is used in substructure coatings. The manufactured samples were installed at the bottom of a ladder in a substructure, and monitored for 10 months. The most biofouling occurred in the sample without the self-polishing property, and algae, barnacles and corallinales were observed. The surface energy analysis used the Owens-Wendt-Rabel and Kaelble (OWRK) model, which uses the contact angles of two standard fluids. As a result of calculating the surface energy using contact angle measurement, the sample without the self-polishing property showed the highest value. This result was consistent with the biofouling incidence observed through monitoring.

• Proceedings of the KIEE Conference
• /
• 1996.11a
• /
• pp.84-87
• /
• 1996

This paper presents a energy function to reflect the control effect of speed governor which has a cut-off property which means position and rate limit The proposed energy function satisfies the semi-negativeness of its time derivative and well reflects the parameters of speed governor to the energy function. The transient stability analysis by the direct method for the single machine infinite bus system has been conducted with the use of the proposed energy function, which shows that the results by the direct method well agree with that by the conventional time simulation method. This thesis shows a possibility of more accurate stability analysis by taking into account the cut-off property of speed governor's output.

• Korean Journal of Computational Design and Engineering
• /
• v.17 no.6
• /
• pp.456-465
• /
• 2012

Nowadays, AEC industry tries to adopt BIM for low-carbon and eco-friendly building development. With increasing environment policies, many of global construction projects require the adoption of BIM for its many advantages. The advantages can be maximized with Open BIM since it can produce optimal results for various purposes of energy performance assessment. However there are some troubles in representation and property information in the process of Open BIM based energy performance assessment. To examine such troubles, this study focuses on differences between IFC of Open BIM and IDF format of Energy Plus known as the most accurate and diverse energy performance assessment. Two issues the study addresses are form representation and property information. The study figures out the different definition of IFC and IDF, and suggests the way of interoperability. The interoperability test of IFC for building energy performance assessment hope to develop of Open BIM based energy assessment.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.458-458
• /
• 2012

Fuel Cell is used stacking metal or polymer substrate. This hydro property of substrate surface is very important. Usually, surface property is hydrophilic. The surface oxidation of SUS is investigated through plasma treatments with an atmospheric-pressure dielectric barrier discharge (DBD) for increasing hydrophilic property. The plasma process makes an experiment under various operating conditions of the DBD, which operating conditions are treatment time, plasma gas mixture ratio, the plasma source supply frequency. Two kinds of SUS substrate, SUS-304 and SUS 316L, were used. Discharge frequency has a crucial impact on equipment performance and gas treatment. After the plasma treatment of a SUS plate, highly improved wettability was noted. But, when high oxygen supply, the substrate damaged seriously.

• Journal of the Korean Society for Heat Treatment
• /
• v.17 no.4
• /
• pp.216-222
• /
• 2004

Study was focused on the quenching embrittlement property of Zircaloy-4 cladding simulated Loss Of Coolant Accident (LOCA) environment in terms of high temperature oxidation and phase transformation. Property in LOCA condition of advanced cladding that contained Nb element was also investigated. Claddings were oxidized at given temperature and given time followed by water quenching. The results showed that ${\beta}$ phase which formed at quenching stage has an influence on cladding property. In case of advanced cladding, Nb retards cladding oxidation, thus enhances quenching resistance.

• International conference on construction engineering and project management
• /
• 2013.01a
• /
• pp.267-273
• /
• 2013

Early design phase energy modeling is used to provide the design team with first order of magnitude feedback about the impact of various building configurations. For better energy-conscious and sustainable building design and operation, the construction of BIM data interoperability for energy performance assessment in the early design phase is important. The purpose of this study is to suggest construction of BIM data interoperability for energy performance assessment based on BIM. To archive this purpose, the authors have investigated advantage of BIM-based energy performance assessment through comparison with traditional energy performance assessment and suggested requirement for construction of open BIM environment such as BIM data creation, BIM data software practical use, BIM data application and verification. In addition, the authors have suggested BIM data interoperability and BIM energy property mapping method focused on materials.

• Journal of Radiation Industry
• /
• v.7 no.1
• /
• pp.45-49
• /
• 2013

In tissue engineering application, a fibrous structure of scaffolds has been issued as an alternative system to regulate cell survival and tissue regeneration, and electrospinning technique has been popularly used to generate fibrous meshes or sheets mimicking the structure of native extracellular matrix (ECM). However, recent strategy in the scaffold development is expanded to provide the structural property as well as a biological property of native ECM, a variety of surface modification techniques have been used to introduce biological property. In this study, we developed biomimetic poly(L-lactide-co-${\varepsilon}$-caprolactone) (PLCL) nano- and micro-fibrous scaffolds as a unique platform with structural and biological properties with native ECM using electrospinning method and gamma-ray irradiation. Surface morphology of the scaffolds was observed by scanning electron microscopy, and alteration of surface property was evaluated with toluidine blue O staining, water contact angle measurement and ATR-FTIR analysis.

• Journal of Korea Foundry Society
• /
• v.36 no.6
• /
• pp.187-194
• /
• 2016

The effects of scrap content on the impact and fatigue properties were investigated in AC4A alloy. The impact absorbed energy of as-cast specimens were 3.61, 3.56, 3.47, and 3.08 Joules, respectively, when scrap contents of the specimens were 0, 20, 35, and 50%. And, the corresponding energy levels of the T6 heat-treated condition were 3.66, 3.48, 3.25, and 2.96 Joule. In the same way, the fatigue strength values of the as-cast specimens were 53.2, 52.0, 48.4, and 43.8MPa, respectively, and the corresponding fatigue strengths of the T6 heat-treatment specimens were 85.4, 75.7, 60.6, and 51.2 MPa. Impact absorbed energy and fatigue strength decreased as scrap content of the specimen increased. It is assumed that impact absorbed energy decreased owing to the presence of oxide films, which act as branches of 2nd cracks; fatigue strength also decreased with decreased deflection of the fatigue crack path as the scrap content of the specimens increased.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2014.10a
• /
• pp.193-196
• /
• 2014

Experimantal evaluation of an energy storage device with high rotational speed to store regenerative energy which might be generated during the braking period of the trains is presented. The proposed ESS is small scale model and has 5kW output power, high rotational speed. In general railway trains generate regenerative energy for 10-20 sec when the train brakes and also high traction energy is needed for very short moment (10 sec) when the train increases the traction force. Considering such characteristics of the railway system energy storage device for the railway should have very fast response property. Among the various energy storage devices flywheel energy storage system has the fastest response property, which means that flywheel ESS is the most suitable for the railway system.