• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.6 no.1
• /
• pp.23-28
• /
• 2010

To enhance the reliability of ultrasonic testing system, MOST(Ministry of Science and Technology) bulletin 2004-13 was published in 2004.6 requiring performance demonstration in ultrasonic examination and MEST(Ministry of Education, Science and Technology) 2009-37 was published in 2009.9(formerly MOST bulletin 2004-13). In order to meet the MEST bulletin requirement and increase the reliability of ultrasonic testing, all the ultrasonic examination procedure and equipment should be performance demonstrated and qualified. In this paper, generic procedure for the ultrasonic examination of dissimilar metal welds are described and new technique are introduced.

• Nuclear Engineering and Technology
• /
• v.39 no.2
• /
• pp.103-110
• /
• 2007

The High Temperature Gas-cooled Reactor (HTGR) possesses inherent safety features and is recognized as a representative advanced nuclear system for the future. Based on the success of the HTR-10, the long-time operation test and safety demonstration tests were carried out. The long-time operation test verifies that the operation procedure and control method are appropriate for the HTR-10 and the safety demonstration test shows that the HTR-10 possesses inherent safety features with a great margin. Meanwhile, two new projects have been recently launched to further develop HTGR technology. One is a prototype modular plant, denoted as HTR-PM, to demonstrate the commercial capability of the HTGR power plant. The HTR-PM is designed as $2{\times}250$ MWt, pebble bed core with a steam turbine generator that serves as an energy conversion system. The other is a gas turbine generator system coupled with the HTR-10, denoted as HTR-10GT, built to demonstrate the feasibility of the HTGR gas turbine technology. The gas turbine generator system is designed in a single shaft configuration supported by active magnetic bearings (AMB). The HTR-10GT project is now in the stage of engineering design and component fabrication. R&D on the helium turbocompressor, a key component, and the key technology of AMB are in progress.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.15 no.6
• /
• pp.26-37
• /
• 2011

A 75-tonf-class LRE(liquid rocket engine) thrust chamber with ablative material for technology demonstration was manufactured on the basis of development technologies of 30-tonf-class LRE. Hydraulic characteristics of the thrust chamber were examined through cold flow test and ignition test of low flow condition. Test result showed that hydraulic function was good. Side ignition method with igniter ring also showed a fine function of ignition in operating ways of static condition. But a close review is required to understand the phenomena of generation and extinction of specific frequencies showed in dynamic characteristics ways. To achieve these, a large combustion test facility which is capable of performing combustion test at design condition of the 75-tonf-class thrust chamber should be constructed as soon as possible.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.23 no.3
• /
• pp.249-257
• /
• 2013

This study newly presents a synthetic phase tuning technique to suppress the unwanted torsional mode while enhancing the desired torsional mode in a pipe. Specifically, we aim at the enhancement of the first torsional mode and the suppression of the undesired, second torsional mode. Earlier efforts were to enhance the desired wave mode only in the hope that the enhancement results in the suppression of the unwanted wave mode. Unlike these efforts, the suggested technique makes the complete cancellation of the unwanted wave mode but it is shown to enhance the desired first mode for torsional wave problems. In the present study, the synthetic phase tuning is developed for the cancellation of the unwanted wave mode, meaning that the number of necessary experimental equipments is reduced. Simulation and experiment were carried out to check the effectiveness of the proposed method. As an application of the suggested technique, we investigated the reflection and mode conversion characteristics of the first torsional mode according to the step thickness variation in a stepped pipe.

• Journal of Korean Society of Water and Wastewater
• /
• v.35 no.1
• /
• pp.1-14
• /
• 2021

Eutrophication and algal blooms can lead to increase of taste and odor compounds and health problems by cyanobacterial toxins. To cope with these eco-social issues, Ministry of Environment in Korea has been reinforcing the effluent standards of wastewater treatment facilities. As a result, various advanced phosphorus removal processes have been adopted in each wastewater treatment plant nation-widely. However, a lot of existing advanced wastewater treatment processes have been facing the problems of expensive cost in operation and excessive sludge production caused by high dosage of coagulant. In this study, the sedimentation and dissolved air flotation (SeDAF) process integrated with sedimentation and flotation has been developed for enhanced phosphorus removal in wastewater treatment facilities. Design and operating parameters of the SeDAF process with the capacity of 100 ㎥/d were determined, and a demonstration plant has been installed and operated at I wastewater treatment facility (located in Gyeonggi-do) for the verification of field applicability. Several empirical evaluations for the SeDAF process were performed at demonstration-plant scale, and the results showed clearly that T-P and turbidity values of treated water were to satisfy the highest effluent standards below 0.2 mg/L and 2.0 NTU stably for all of operation cases.

• Smart Media Journal
• /
• v.7 no.1
• /
• pp.24-30
• /
• 2018

Acquisition of the FIDO authentication technology in pursuit of improved security function of the NFC-based 2 factor electronic payment system enabled GenoTech Ch., Ltd. to develop its new service, Gallery-Auction, demoed at Daegu Exhibition. The demonstration was followed by the improvement requests in banner creation & installation, changes in UI, changes in order of operation, etc, which were taken into account for the succeeding update. During the second demonstration held at 'Art: Gwangju: 17,' it analyzed and visualized the number of visitors per hour there.

• Ocean and Polar Research
• /
• v.38 no.1
• /
• pp.71-79
• /
• 2016

In this study, we attempt to examine the economic impacts of the CCS marine geological storage demonstration project in Korea using Input-Output analysis utilizing the inter-industry relation table issued in 2013. In particular, this study defines the $CO_2$ ocean storage industry and then added the inter-industry relation table and treated the $CO_2$ ocean storage industry as exogenous. In addition, this study assumed two scenarios based on the means of $CO_2$ transport, which are pipe and ship. After defining the industry and scenarios, this study investigates the production-inducing effect, value added inducing effect, and employment-inducing effect of the industries associated with the $CO_2$ ocean storage industry based on a demand-driven model. The results pertaining to the scenarios are estimated as follows: total production-inducing effects, value added inducing effects, and employment-inducing effects are calculated as 1.9044 won, 1.2487 won and 16.7224 people/billion won, respectively. In addition, compared to other industries, the indirect economic impacts of the $CO_2$ ocean storage industry are ranked high: the rankings of production-inducing effects, value added inducing effects, and employment-inducing effects are fourth, second, and fifth, respectively.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.25 no.1
• /
• pp.48-57
• /
• 2015

In a sodium-cooled fast reactor, which is a Generation-IV reactor, refueling is conducted by rotating, but not opening, the reactor head to prevent a reaction between the sodium, water and air. Therefore, an inspection technique that checks for the presence of any obstacles between the reactor core and the upper internal structure, which could disturb the rotation of the reactor head, is essential prior to the refueling of a sodium-cooled fast reactor. To this end, an ultrasound-based inspection technique should be employed because the opacity of the sodium prevents conventional optical inspection techniques from being applied to the monitoring of obstacles. In this study, a ranging inspection technique using a plate-type ultrasonic waveguide sensor was developed to monitor the presence of any obstacles between the reactor core and the upper internal structure in the opaque sodium. Because the waveguide sensor installs an ultrasonic transducer in a relatively cold region and transmits the ultrasonic waves into the hot radioactive liquid sodium through a long waveguide, it offers better reliability and is less susceptible to thermal or radiation damage. A 10 m horizontal beam waveguide sensor capable of radiating an ultrasonic wave horizontally was developed, and beam profile measurements and basic experiments were carried out to investigate the characteristics of the developed sensor. The beam width and propagation distance of the ultrasonic wave radiated from the sensor were assessed based on the experimental results. Finally, a feasibility test using cylindrical targets (corresponding to the shape of possible obstacles) was also conducted to evaluate the applicability of the developed ranging inspection technique to actual applications.

• Asian-Australasian Journal of Animal Sciences
• /
• v.33 no.3
• /
• pp.480-489
• /
• 2020

Objective: Sow milk (SM) may not be able to meet the piglet's nutritional needs in late lactation. Hence, this study was conducted to investigate the effects of early commercial milk (CM) supplement on the mucosal morphology, bacterial community and bacterial metabolites in jejunum of piglets. Methods: Ten litters of newborn piglets ([Yorkshire×Landrace]×Duroc) were randomly divided into 2 groups of 5 litters. The piglets in the control group were suckled by the sow (SM), while the piglets in the treatment group (CM supplement) were supplemented with a CM supplement along with suckling from d 4 to d 28 of age. Results: No significant differences were observed about jejunal mucosal morphology on d 28 and d 35 between two groups. On d 28, the activity of lactase in the jejunum was significantly decreased in the CM group, while the activity of sucrase and the ratio of maltase to lactase were significantly increased (p<0.05). On d 35, the activity of maltase in the jejunum was significantly increased in the CM group (p<0.05), and maltase to lactase ratio tended to increase in the CM group (p = 0.065). In addition, piglets in the CM group had a higher abundance of Clostridium XI, Tuicibater, and Moraxella in the jejunum on d 28, while the abundance of Lactobacillus was significantly increased on d 35 (p<0.05). Conclusion: The early CM supplement improved the maturation of the jejunum to some extent by enhancing the maltase and sucrase activities. Moreover, the early CM supplement could help maintain the homeostasis of internal environment in jejunum by increasing the microbial-derived metabolites.

• Asian-Australasian Journal of Animal Sciences
• /
• v.33 no.12
• /
• pp.2008-2020
• /
• 2020

Objective: This study was conducted to investigate the effects of dietary corn resistant starch (RS) on the intestinal morphology and barrier functions of broilers. Methods: A total of 320 one-day-old broilers were randomly allocated to 5 dietary treatments: one normal corn-soybean (NC) diet, one corn-soybean-based diet supplementation with 20% corn starch (CS), and 3 corn-soybean-based diets supplementation with 4%, 8%, and 12% corn resistant starch (RS) (identified as 4% RS, 8% RS, and 12% RS, respectively). Each group had eight replicates with eight broilers per replicate. After 21 days feeding, one bird with a body weight (BW) close to the average BW of their replicate was selected and slaughtered. The samples of duodenum, jejunum, ileum, caecum digesta, and blood were collected. Results: Birds fed 4% RS, 8% RS and 12% RS diets showed lower feed intake, BW gain, jejunal villus height (VH), duodenal crypt depth (CD), jejunal VH/CD ratio, duodenal goblet cell density as well as mucin1 mRNA expressions compared to the NC group, but showed higher concentrations of cecal acetic acid and butyric acid, percentage of jejunal proliferating cell nuclear antigen-positive cells and delta like canonical Notch ligand 4 (Dll4), and hes family bHLH transcription factor 1 mRNA expressions. However, there were no differences on the plasma diamine oxidase activity and D-lactic acid concentration among all groups. Conclusion: These findings suggested that RS could suppress intestinal morphology and barrier functions by activating Notch pathway and inhibiting the development of goblet cells, resulting in decreased mucins and tight junction mRNA expression.