• Journal of the Korean Society of Propulsion Engineers
• /
• v.18 no.3
• /
• pp.84-91
• /
• 2014

The flow rate control of a cavitating venturi has been investigated with downstream pressure variation. A set of cavitating venturies for a liquid rocket engine thrust chamber firing test facility have been designed and manufactured. The flow characteristics of the cavitating venturies have been analyzed by experimental and computational methods. Results showed that constant mass flow rate condition was established by the cavitation inside the venturi. However, upstream pressure less than the actual design pressure of the cavitating venturi could not supply a constant flow rate.

• 보존과학연구
• /
• s.23
• /
• pp.95-112
• /
• 2002

Seoul City built a facility for conservation of the Wongaksajisipcheungseoktap (Ten storied stone pagoda of Wongaksa Temple site, National treasure No. 2). It has speciality glass(thickness 21.5㎜) between steel-frames(8.4m, length 8.4m, height 15.4m). So we investigated the inside of facility to know whether the environment alvariation exists. We measured continuously the temperature and relative humidity, twice for the particulate, once for the $SO_2$(sulfur dioxide), $NO_2$(nitrogen dioxide)and $O_3$(ozone) from September $1_st$, 2000 to August $31_st$, 2001.The temperature and relative humidity, have a tendency to vary, and they have no difference between the inside and the outside. As dewy phenomenon doesn appear on the surface of the Pagoda and facility we know that the inside air is moving. As a result of the particulate is $64\mug$/$m_3$ of average concentration, the particulate fluxed inside don’t flow out because air-velocity of the outside is faster than that of the inside. The air pollutants are 0.036ppm/hr of SO$_2$average concentration, 0.028ppm/hr of $NO_2$ average concentration and 0.008ppm/hr of $O_3$ average concentration which are lower than the Environmental Air Quality Standards($SO_2$ : 0.15ppm/hr, $NO_2$ : 0.25ppm/hr,O3 : 0.1ppm/hr).

• Fire Science and Engineering
• /
• v.32 no.6
• /
• pp.91-99
• /
• 2018

Recently, the spread of ESS in Korea has increased and a fire accident has also occurred. By July 2018, there were a total of 7 cases. All 7 cases were ESS systems consisting of lithium-ion batteries and were burned down. Both the automatic fire extinguisher and the fire department were not able to digest. In this paper, the characteristics of ESS fire are analyzed based on recent ESS fire situation and field investigation, and the cause of fire is divided into environmental, electrical and thermal factors. As a result, it was found that the ESS fire was correlated with the installation environment of the system. In the domestic and overseas lithium ion battery test standard and ESS facility standard survey, the trends and differences of domestic and overseas facilities standards were identified. Based on the fire status and field investigationy, and domestic and overseas facility standard survey, measures were suggested to prevent and prevent the spread of fire in ESS fire.

• Smart Media Journal
• /
• v.11 no.4
• /
• pp.9-18
• /
• 2022

Recently, research and system using AI is rapidly increasing in various fields. Smart farm using artificial intelligence and information communication technology is also being studied in agriculture. In addition, data-based precision agriculture is being commercialized by convergence various advanced technology such as autonomous driving, satellites, and big data. In Korea, the number of commercialization cases of facility agriculture among smart agriculture is increasing. However, research and investment are being biased in the field of facility agriculture. The gap between research and investment in facility agriculture and open-air agriculture continues to increase. The fields of fruit trees and plant factories have low research and investment. There is a problem that the big data collection and utilization system is insufficient. In this paper, we are proposed the system for determining the fruit tree growth stage using a deep learning-based object detection model. The system was proposed as a hybrid app for use in agricultural sites. In addition, we are implemented an object detection function for the fruit tree growth stage determine.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.5B no.3
• /
• pp.289-295
• /
• 2005

Instrumentation and Control (I&C) of the Neutral Beam Test Stand (NB- TS) Facility at the Korea Atomic Energy Research Institute (KAERI) for the Korea Superconducting Tokamak Advanced Research (KSTAR) project has been underway since the start of the project to answer the diverse requests arising from the various facets of the development and construction phases of the project. Optical signal transmission constitutes a significant portion of I&C works and has been performed for the entirety of the project. During the NB- TS construction and related experiments, significant achievements to a more accurate as well as more refined optical signal transmissions have been made. Examples of those I&C works that utilized the optical signal transmission are the Langmuir probe signal transmission, gradient grid current signal transmission, gas flow control and signal transmission, ion source temperature measurement, beam line component temperature monitoring, and coolant flow signal transmission, etc. These optical signal transition provisions are now performing part of the indispensable functions for the proper operation of the NB- TS facility. Attained experience and expertise are expected to be well applied to the upcoming main neutral beam injection (NBI) system construction for the KSTAR project.

• KIEAE Journal
• /
• v.7 no.2
• /
• pp.77-85
• /
• 2007

Korean society expects to be changing into aged society more rapidly than any other countries due to low birthrate and increase in life expectancy. Increasing number of elderly and social problems of aging society have provoked increase in research on elderly environment. Elderly housing facilities and living conditions are significantly related to the quality of life for older persons. The purpose of this study is to systematically analyze empirical studies on elderly physical environments in Korea, find out research streaming and understand social backgrounds and to suggest future research problems. For this study, contents analysis was conducted. Articles of four academic peer reviewed journals published from 1986 to 2005 were units of analysis. Using a keyword through library database systems, the articles were systematically selected. As results, trends of research according to 4 periods were defined. Among them as major trends, expansion of the quantity, expansion to interior design features for older persons, more facility types for dependent elderly(assisted living facilities, facilities for elderly with dementia, long term care facilities) have appeared. This result showed some directions and implications on elderly facility planning and development.

• Journal of Radiation Protection and Research
• /
• v.32 no.4
• /
• pp.190-193
• /
• 2007

The objective of this study is to recommend the radiation protection design parameters from the shielding point of view for concrete wall between the decay tank room and the primary pump room in TRIGA Mark-II Research Reactor Facility. The shield design for this concrete wall has been performed with the help of Point-kernel Shielding Code Micro-Shield 5.05 and this design was also validated based on the measured dose rate values with Radiation Survey Meter (G-M Counter) considering the ICRP-60 (1990) recommendations for occupational dose rate limit ($10{\mu}Sv/hr$). The recommended shield design parameters are: (i) thickness of 114.3 cm Ilmenite-Magnetite Concrete (IMC) or 129.54 cm Ordinary Reinforced Concrete (ORC) for concrete wall A (ii) thickness of 66.04 cm Ilmenite-Magnetite Concrete (IMC) or 78.74 cm Ordinary Reinforced Concrete (ORC) for concrete wall B and (iii) door thickness of 3.175 cm Mild Steel (MS) on the entrance of decay tank room. In shielding efficiency analysis, the use of I-M concrete in the design of this concrete wall shows that it reduced the dose rate by a factor of at least 3.52 times approximately compared to ordinary reinforced concrete.

• Nuclear Engineering and Technology
• /
• v.52 no.2
• /
• pp.429-447
• /
• 2020

The considered simulation tasks are based on an electrometallurgical process development strategy and associated telemanipulator simulation systems are proposed with various scales of experimental facilities. Fundamentally, target facilities are assumed to be operated only by remote handling systems because the considered process is operated in hazardous environments. Futhermore, the feasibility at various scales should be experimentally verified with gradual increase in throughput. In this regard, bench, engineering, and pilot-scale simulation systems are important early-stage tools for assessing the practical operability of the target process with the material handling systems. Such simulation systems are highly customized for applications and are a precursor to larger pilot and demonstration-scale plants. This paper introduced and classified the developed simulator systems for this approach at various scales using remote handling systems which were assembled inside a virtual target facility, and the manmachine interface was included for a more realistic operation of the simulator. The results obtained for each simulator show the feasibility and requirement for improvement of the systems for the considered test issues with respect to the operation and maintenance of the process.

• Corrosion Science and Technology
• /
• v.15 no.5
• /
• pp.245-252
• /
• 2016

The pipelines and equipments are degraded by flow-accelerated corrosion (FAC), and a large-scale test facility was constructed for simulate the FAC phenomena in secondary coolant environment of PWR type nuclear power plants. Using this facility, FAC test was performed on weld pipe (carbon steel and low alloy steel) at the conditions of high velocity flow (> 10 m/s). Wall thickness was measured by high temperature ultrasonic monitoring systems (four-channel buffer rod type and waveguide type) during test period and room temperature manual ultrasonic method before and after test period. This work deals with the complex effects of flow velocity on the wall thinning in weld pipe and the test results showed that the higher flow velocity induced different increasement of wall thinning rate for the carbon steel and low alloy steel pipe.

• Corrosion Science and Technology
• /
• v.20 no.4
• /
• pp.189-195
• /
• 2021

A technology for designing and licensing a dedicated radiation shielding facility needs to be developed for safe and efficient operation an R&D center. Technology development is important for smooth operation of such facilities. Causes of damage to internal structures (such as baffle former bolt (BFB) of pressurized water reactor) of a nuclear power reactor should be analyzed along with prevention and countermeasures for similar cases of other plants. It is important to develop technologies that can comprehensively analyze various characteristics of internal structures of long term operated reactors. In high-temperature, high-pressure operating environment of nuclear power plants, cases of BFB cracks caused by irradiated assisted stress corrosion cracks (IASCC) have been reported overseas. The integrity of a reactor's internal structure has emerged as an important issue. Identifying the cause of the defect is requested by the Korean regulatory agency. It is also important to secure a foundation for testing technology to demonstrate the operating environment for medium-level irradiated testing materials. The demonstration testing facility can be used for research on material utilization of the plant, which might have highest fluence on the internal structure of a reactor globally.