• Nuclear Engineering and Technology
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• v.40 no.2
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• pp.133-138
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• 2008

The use of Supercritical Fluids(SCF) has been proposed for numerous power cycle designs as part of the Generation IV advanced reactor designs, and can provide for higher thermal efficiency. One particular area of interest involves the behavior of SCF during a blowdown or depressurization process. Currently, no data are available in the open literature at supercritical conditions to characterize this phenomenon. A preliminary computational analysis, using a homogeneous equilibrium model when a second phase appears in the process, has shown the complexity of behavior that can occur. Depending on the initial thermodynamic state of the SCF, critical flow phenomena can be characterized in three different ways; the flow can remain in single phase(high temperature), a second phase can appear through vaporization(high pressure low temperature) or condensation(high pressure, intermediate temperature). An experimental facility has been built at the University of Wisconsin to study SCF depressurization through several diameter breaks. The preliminary results obtained show that the experimental data can be predicted with good agreement by the model for all the different initial conditions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.117-122
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• 2006

Modernized GNSS such as new GPS signals updated GLONASS and coming Galileo promises higher quality and higher reliability for users. Powerful technologies such as Internet, ubiquitous network technology and sensor network has been used to promote a safe and more secure lifestyle. This report describes experimental trials to combine these technologies namely GPS and Sensor Network into a high-performance system. GPS is used to enlarge the communication range, resolving the service area limitations, as a wider service area is required at shore areas compared to urban area. GPS position datum is also used as primary network routing information to get practical Sensor Network. Another application is the under water Sensor Network. Accurate GPS position and time are used to establish stable and high reliability underwater acoustic Sensor Network. This paper describes the background of the project 'Harbor area Marine Ubiquitous Sensor Network', preliminary consideration and testing. Radio and acoustic communication is the main focus of this preliminary experiment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.10
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• pp.859-870
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• 2021

KARI (Korea Aerospace Research Institute) is developing a design framework for the concept and preliminary design of eVTOL aircrafts. A low fidelity mission analysis tool was developed for the eVTOL aircrafts of Lift-Tilt Concept, which have tilt propellers and lift propellers, using open source SUAVE package. For its development, a review for the propeller performance analysis functionality was made. To find the trim solution at each mission segment automatically, an algorithm is implemented, using a global optimization technique through parallel processings and DOE(design of experiment). Using the tool, the one seated eVTOL OPPAV(optionally piloted personal air vehicle) was modeled and evaluated, which results were compared with the preliminary design data.

• Journal of Distribution Science
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• v.19 no.3
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• pp.61-70
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• 2021

Purpose: This paper reviews the attitudes of consumers related to the consumption crisis response strategy (i.e., defensive vs. receptive) that companies implement during crises. Research design, data, and methodology: We discuss the interaction between the crisis response strategy and the consumption crisis type (i.e., corporate ability vs. corporate social responsibility). We used SAS ver. 9.4 software to analyze the results. We applied a 2 × 2 intergroup experimental design to our sample of subjects, who were undergraduate and graduate students at a university in Seoul, South Korea. The three experimental variables considered were the entity's risk response strategy, the crisis type, and public relations strategy. The experiments were conducted by presenting a hypothetical scenario to eight groups. Prior to this experiment, five preliminary surveys were conducted to determine the three variables just mentioned. Preliminary surveys were conducted on the basis of these criteria. For eight selected product lines, 320 undergraduates were required to enter the product lines that are frequently used in the assessment center up to the fourth priority. Results: Analysis of variance revealed that experiments related to crisis response strategy, type of enterprise crisis, and type of public relations message were successful. Conclusions: Our results verify the impact of different types of social initiatives on distribution marketplaces.

• Journal of Astronomy and Space Sciences
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• v.40 no.4
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• pp.131-148
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• 2023

Lunar permanently shadowed regions (PSRs) never see direct sunlight and are illuminated only by secondary illumination - light reflected from nearby topography. The ShadowCam imaging experiment onboard the Korea Pathfinder Lunar Orbiter is acquiring images of these PSRs. We characterize and discuss the nature of secondary illumination for the Shackleton PSR from ShadowCam radiance-calibrated images. We also use modeling to understand the magnitude and direction of the secondary illumination. Results from our analysis highlight the non-homogeneous, dynamic, and complex nature of PSR secondary lighting. Knowledge of the direction of the secondary illumination is crucial for reli-able interpretation of contrasts observed in ShadowCam images. This preliminary analysis of the floor of Shackleton crater from images acquired over multiple secondary illumination conditions does not reveal indications of exposed surface ice, even though temperatures are constantly below 110K.

• Journal of KIISE:Software and Applications
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• v.34 no.10
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• pp.900-909
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• 2007

This paper describes an experiment on the evaluation of human sensibility by monitoring responses to changes In the frequency and amplitude of a tactile display system. Preliminary tasks were performed to obtain effective adjectives concerning texture perception. The number of collected adjectives was originally 33. This number of adjectives was reduced to 14 by a suitability survey that asked whether an adjective is suitable for expressing a texture feeling. Finally after performing a semantic similarity evaluation, the number of adjectives was further reduced to ten and these ten were used in the main experiment. In the main experiment, selected sandpaper types and 15 selected combinations of frequencies and amplitudes of a tactile display were utilized to quantitatively evaluate the ten adjectives using a bipolar seven-point scale. The data show that a relationship exists between the independent variables(frequency, amplitude, and grit site) and the dependent variable(perceived texture). That is, the change of frequency and amplitude is directly related to perceived roughness or essential elements of human tactile sensitivity found in the preliminary experiment.

• Tunnel and Underground Space
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• v.33 no.3
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• pp.109-125
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• 2023

Disposal repository for high-level radioactive waste secures its safety by means of engineered and natural barriers. The performance of these barriers should be tested and verified through various aspects in terms of short and/or long-term. KAERI has been conducting various in-situ demonstrations in KURT (KAERI Underground Research Tunnel). After completing previous experiment, a conceptual design of an improved in-situ experiment, i.e. K-COIN (KURT experiment of THMC COupled and INteraction), was established and detailed planning for the experiment is underway. Preliminary characterizations were conducted in KURT for siting a K-COIN test site. 15 boreholes with a depth of about 20 m were drilled in three research galleries in KURT and intact rock specimens were prepared for laboratory tests. Using the specimens, physical measurements, uniaxial compression, indirect tension, and triaxial compression tests were conducted. As a result, specific gravity, porosity, elastic wave velocities, uniaxial compressive strength, Young's modulus, Poisson's ratio, Brazilian tensile strength, cohesion, and internal friction angle were estimated. Statistical analyses revealed that there did not exist meaningful differences in intact rock properties according to the drilled sites and the depth. Judging from the uniaxial compressive strength, which is one of the most important properties, all the specimens were classified as very strong rock so that mechanical safety was secured in all the regions.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.5
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• pp.742-752
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• 2020

Objective: This study investigated the effects of vitamin A (VA) supplementation during late-stage pregnancy on longissimus dorsi muscle tissue development, birth traits, and growth performance of postnatal Korean native calves. Methods: In the preliminary experiment, twenty-six pregnant cattle (initial body weight [BW] = 319 kg (standard deviation [SD] = 30.1; 1st parity) were randomly assigned to the control and treatment groups. The treatment group received VA supplementation at 24,000 IU/d from gestational day 225 until delivery. In the main experiment, twelve pregnant cattle (initial BW = 317 kg [SD = 31.3]; 1st parity) were treated with VA supplementation at 24,000 IU/d (gestational days 150 to 225) and at 78,000 IU/d (gestational day 225 until delivery). Serum VA levels were analyzed in pregnant cattle, and the growth performance, gene expression, and serum VA levels were analyzed in the offspring. Results: Serum VA levels in pregnant cattle decreased the late gestation in both experiments (p<0.001). In the main experiment, pregnant cattle at parturition and offspring at birth in the treatment group had higher serum VA levels than those in the control group (p<0.05). In the treatment groups, an increased birth weight was observed in the main experimental group (p = 0.022), and a tendency (p = 0.088) toward an increased birth weight was observed in the preliminary experimental group. However, no differences were observed in the feed intake, average daily gain, gain-to-feed ratio, or BW of 31-day-old calves. Gene expression was analyzed in longissimus dorsi muscles of 31-day-old calves. VA supplementation in pregnant cattle stimulated postnatal muscle development in offspring by elevating myogenic factor 5 (MYF5), MYF6, and myoblast determination levels (p<0.05). Moreover, preadipocyte-related marker genes such as extracellular signal-regulated kinase 2 and krüppel-like factor 2 were higher in the treatment group than in the control group (p<0.05). Conclusion: VA supplementation (78,000 IU/d) in late-stage pregnant cattle maintained serum VA levels. In addition, 78,000 IU/d VA supplementation increased the birth weight and expression of genes related to muscle and preadipocyte development in offspring. Overall, 78,000 IU/d VA supplementation in pregnant cattle is beneficial to newborn calves.

• Ecology and Resilient Infrastructure
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• v.2 no.4
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• pp.284-290
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• 2015

In this study, two hypotheses were examined to preliminarily verify for the vegetation recruitment and establishment on riparian bars in unregulated rivers; hydrologic regime change and nutrients influx into streams. In order to preliminarily verify the first hypothesis, precipitation patterns were analyzed during a period from March through to May when reeds, the most common riparian vegetation in Korea, germinate and start to grow in riparian areas. The results show that during the last 35 years, the total precipitation during the three-month period decreased by about 15 %, while the total annual one increased by about 15% in Korea. In order to verify the second hypothesis, a preliminary experiment was conducted with a set of two-vegetative flumes for one year. In this experiment, a stream flow with reeds on the riparian sand bars was simulated with a flume with reeds planted on the sand bed and water with a concentration of 3.5 mg of N flowing in the flume for four hours. For comparison, clean water was circulated in the same way in another flume for simulating a stream flow without N. The experimental results show that the growth rate of reeds in N-mixed flow exceeds that in clean water flow by about 30%. The above two results could explain the phenomenon of change in unregulated rivers from white river to green river in Korea, although they were obtained through limited extents of analysis and experiment.

• Journal of Korean Physical Therapy Science
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• v.8 no.2
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• pp.989-995
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• 2001

The purpose of this paper was to enable patients, who suffer from muscle damage. to return to their normal activities as soon as possible. With this in mind. this experiment was carried out to make an analysis of a variety of ingredients subjected to changes when muscle damage or muscle soreness was treated with aceclofenac, NSAID, and to find out what effect the anti-inflammation produced in relation to such symptoms. It made use of male rats (Sprague-Dawely) as subjects. It carried out two kinds of experiments: one was a preliminary experiment from March 15, 2001 to March 20, 2001 and the other was a main experiment from March 30, 2001 to April 15, 2001. Each group was composed of five rats. In case of DOMS. it worked with eight male adults from April 20. 2001 to April 30, 2001. It have come up with the following conclusions: 1. The leucocytes and erythrocytes of the experiment group were decreasing with the lapse of time in comparison with those of the contrast group. And a decrease in the number of hemoglobin had remarkably statistic significance (P<0.05). 2. Neutrophil, Lymphocyte and Monocyte decreased in 36, 24, 12 and 24 hours, respectively, which means that they had a significant difference(P<0.05). 3. CPK and LDH were reduced remarkably through the whole time slot in comparison with the contrast group, and had statistic significance(P<0.05). The findings above show that anti-inflammations cure bruises or damage or myalgia in a shorter period of time than the normal recovery of other treatment.