• Korean Journal of Veterinary Research
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• v.46 no.1
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• pp.27-34
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• 2006

This paper describes the slaughter check results of breeding pigs from the Korean Swine Testing Station for the control of endemic diseases. Gross lesions monitored in the present study included those conditions commonly associated with economically significant subclinical herd infections: enzootic pneumonia, pleuropneumonia, pleuritis, atrophic rhinitis, liver white spots, papular dermatitis and ileitis. A total of 128 slaughter pigs were investigated at 4 subsequent tests according to the slaughter check procedures established. The prevalence of enzootic pneumonia, pleuropneumonia and pleuritis in the initial test was 67.9%, 28.6% and 17.9%, respectively. However, these were decreased to 46.7%, 6.7% and 6.7%, respectively, in the last test after implementation of counter measures including clean-up protocols and medication programs (p > 0.05). The mean pneumonic score also significantly decreased from 6.8 in the initial test to 2.8 in the last test. The prevalence of atrophic rhinitis (${\geq}score\;2$) was 32.2% and mean atrophic rhinitis score of 1.1 were recorded. However, no significant improvement of conditions was achieved with the counter measures indicating that atrophic rhinitis was originated from the source herds and lesions developed early in the life. In the initial test, prevalence of liver white spots and papular dermatitis lesions was 21.4% and 25.0%, respectively. These conditions were cleaned by the implementation of parasite control measures with all-in all-out, strict clean-up protocols and proper medications adopted in the present study (liver white spots, p = 0.0124; papular dermatitis lesions, p = 0.0055). The prevalence of ileitis lesions in slaughter pigs from the initial test was 28.6%, it could be gradually reduced by the use of repeated treatments and control measures but the effect was not so significant (p > 0.05). In conclusion, slaughter check procedures were successfully established and applied for the control of endemic diseases in the Korean Swine Testing Station.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.429-432
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• 2008

Large area members such as foundation concrete of underground structures in power plants have an effect on structural stability and durability of the structure due to danger of crack occurrence and shrinkage crack that occur owing to the difference of temperature by heat of hydration between inside and outside of the members at initial age. And a construction for waterproofness is performed additionally to protect marine structures from osmosis of seawater because the structures adjoin below the surface of sea. So, if a rise of the heat of hydration, crack, and corrosion of bars are controled effectively using a composite such as fluosilicate salt in concrete production process of a initial construction, expenses are cut down and construction hours are reduced by securing durability through improvement of watertightness. The property tests of adiabatic temperature by hydration are carried out at initial age about standard concrete and test concrete using a fluosilicate salt composite to evaluate an effect on improvement of watertightness for concrete structures in this study. And the experiments such as a permeability test of hardened concrete, a water absorption test, a compression strength test and a elongation test are carried out and the results from these are described.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.57.2-57.2
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• 2013

Cosmology is entering an era of percent precision with large surveys, demanding accurate simulations. In this paper, we aim to study the effects of initial conditions on the results of cosmological simulations, which will help us to make percent-level accuracy simulations. For this purpose, we use a series of cosmological N-body simulations with varying initial conditions. We test the influence of the initial conditions, namely the pre-initial configuration (preIC), the order of the perturbation theory, and the initial redshift, on the statistics associated with the large scale structures of the universe such as the halo mass function, the density power spectrum, and the maximal extent of the large scale structures. We find that glass or grid pre-initial conditions give similar results. However, the order of the Lagrangian perturbation theory used to generate the initial conditions and the starting epoch of the simulations play a crucial role, especially at high redshift (z ~ 2-4). The initial conditions have to be chosen with care, taking into account the specificity of the simulation.

• Nuclear Engineering and Technology
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• v.41 no.1
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• pp.53-62
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• 2009

A set of experiments has been conducted on the performance sensitivity of the passive residual heat removal system (PRHRS) for an advanced integral type reactor, SMART, by using a high temperature and high pressure thermal-hydraulic test facility, the VISTA facility. In this paper the effects of the opening delay of the PRHRS bypass valves and the closing delay of the secondary system isolation valves, and the initial water level and the initial pressure of the compensating tank (CT) are investigated. During the reference test a stable flow occurs in a natural circulation loop that is composed of a steam generator secondary side, a secondary system, and a PRHRS; this is ascertained by a repetition test. When the PRHRS bypass valves are operated 10 seconds later than the secondary system isolation valves, the primary system is not properly cooled. When the secondary system isolation valves are operated 10 or 30 seconds later than the PRHRS bypass valves, the primary system is effectively cooled but the inventory of the PRHRS CT is drained earlier. As the initial water level of the CT is lowered to 16% of the full water level, the water is quickly drained and then nitrogen gas is introduced into the PRHRS, resulting in the deterioration of the PRHRS performance. When the initial pressure of the PRHRS is at 0.1MPa, the natural circulation is not performed properly. When the initial pressures of the PRHRS are 2.5 or 3.5 MPa, they show better performance than did the reference test.

• The Journal of the Acoustical Society of Korea
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• v.30 no.5
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• pp.295-302
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• 2011

The purpose of this study was to develop Korean Consonant Perception Test (KCPT), that is a phonemic level including elementary data to evaluate speech and consonant perception ability of the normal and the hearing impaired qualitatively and quantitatively. KCPT was completed with meaningful monosyllabic words out of possible all Korean monosyllabic words, considering articulation characteristics, the degree of difficulty, and the frequency of the phonemic appearance, after assembling a tentative initial and final consonants testing items using four multiple-choice method which were applied to the seven final consonant regulation and controlled with the familiarity of the target words. Conclusively, the final three hundred items were developed including two- and one-hundred items for initial and final testing items, respectively, with the evaluation of the 20 normal hearing adults. Through this process, the final KCPT was composed upon the colloquial frequency following identification of no speakers' variances statistically and elimination of the highly difficult items. The 30 hearing impaired were tested with KCPT and found that the half lists, A and B, were not different statistically and the initial and final testing items were appropriate for evaluating initial and final consonants, respectively.

• Journal of Periodontal and Implant Science
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• v.44 no.1
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• pp.20-24
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• 2014

Purpose: The aim of this clinical trial was to explore the impact of intentional passive eruption (IPE) using occlusal reduction on the periodontal parameters of teeth with moderate chronic periodontitis and traumatic occlusion. Methods: This study was performed on 40 teeth from 16 subjects. At baseline, 4 weeks after initial periodontal treatment, and 6 months after IPE, clinical and radiographic examinations were performed. The 20 teeth in the test group underwent IPE using occlusal reduction, whereas the 20 control teeth did not undergone occlusal reduction. Results: All the periodontal parameters were improved by the initial periodontal treatment. The teeth in the test group showed a significantly greater decrease in pocket depth, tooth mobility, and marginal bone loss than did the control group (P<0.05), but there were no significant changes in the attachment level. Significantly greater improvements in all the parameters were observed in the test group after 6 months of IPE compared to 4 weeks after the initial periodontal treatment (P<0.05). Conclusions: Within the limits of this study, performing initial periodontal therapy combined with IPE using occlusal reduction was shown to be very simple and effective. Moreover, IPE would be helpful in improving periodontal parameters.

• Structural Engineering and Mechanics
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• v.41 no.1
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• pp.43-65
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• 2012

The primary objective of this study was to identify concrete contribution to the initial shear strength of reinforced concrete (RC) hollow columns under lateral loading. Seven large-scale RC rectangular hollow column specimens were tested under monotonic or cyclic lateral loads. The most important design parameter was column length-to-depth aspect ratio ranging between 1.5 and 3.0, and the other test variables included web area ratio, hollow section ratio, and loading history. The tests showed that the initial shear strength reduced in a linear pattern as the column aspect ratio increased, and one specimen tested under cyclic loading achieved approximately 83% of the shear strength of the companion specimen under monotonic loading. Also, several pioneering shear models proposed around the world, all of which were mainly based on tests for columns with solid sections, were reviewed and compared with the test results of this study, for their possible applications to columns with hollow sections. After all, an empirical equation was proposed for concrete contribution to the initial shear strength of RC hollow columns based on fundamental mechanics and the test results.

• Tribology and Lubricants
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• v.38 no.6
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• pp.227-234
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• 2022

Recently, the demand for improving energy efficiency has rapidly increased because of the growing concerns over environmental issues. In this work, the tribo-test and simulation for the initial wear and lubrication performance were performed for the piston pin in the small end system of the connecting rod of a marine engine, to obtain useful data for improving the efficiency of marine engine systems. In addition, a diamond-like carbon (DLC) coating was applied to the piston pin to explore feasibility of eliminating the bush used in the system. The initial wear and lubrication characteristics between the uncoated piston pin and bush were compared with that between the DLC-coated piston pin and connecting rod in the tribo-test. The simulation for the wear and lubrication performance according to the wear progression was conducted based on the data obtained from the test. The wear characteristics were quantitatively assessed by the wear depth and wear volume, and the lubrication performance was characterized with the change of pressure and minimum oil film thickness with respect to the crank angle. It was found that the DLC-coated piston pin may provide better initial wear characteristics and lubrication performance. The results of this work may provide fundamental information for marine engines with improved efficiency.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.1
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• pp.5-12
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• 2004

This paper includes the comparative study between Cr plating and nitriding process with an aim at improving corrosion, wear and maintainability for KNR(Korean Next Generation Rifle) 5.5mm barrel. The endurance test was conducted to compare the performance of standard barrel, Cr plating barrel and nitriding barrel. Main activities are described as follows; optimal Cr plating and nitriding process set-up for KNR 5.56mm barrel; durability test of each barrel(20,000 rounds); salt water immersion test; dispersion, initial velocity, inner diameter data acquisition. According to the results of this firing test, Cr plating barrel is superior to standard barrel and nitriding barrel in view of corrosion, wear and maintainability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.1
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• pp.120-129
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• 2020

This paper aims to benchmark the United States' LRIP, the country's initial production policy, and provide a Korean version of such policy which reflects the circumstances of the country's weapon system research & development(R&D) and acquisition procedures. The research suggests measures to improve the country's initial production policy in a direction that the policy could execute two stage continuously: (1) employment test & evaluation(OT&E), conducted on prototypes during the development stage, and (2) field employment tests(FT), conducted on initial products during the production stage. In addition, the research provides an equation calculating the optimal number of initial test products to be produced, applying statistical theories of t-distribution. The research aims to be used a reference to calculate the optimal number of initial products to be produced for testing in order to improve future national defense acquisition systems and the stable R&D of weapons systems.