• Structural Engineering and Mechanics
• /
• v.69 no.5
• /
• pp.537-545
• /
• 2019

Stress analysis of bottom-hole rock has to be considered with much care to further understand rock fragmentation mechanism and high penetration rate. This original study establishes a fully coupled simulation model and explores the effects of overburden pressure, horizontal in-situ stresses, drilling mud pressure, pore pressure and temperature on the stress distribution in bottom-hole rock. The research finds that in air drilling, as the well depth increases, the more easily the bottom-hole rock is to be broken. Moreover, the mud pressure has a great effect on the bottom-hole rock. The bigger the mud pressure is, the more difficult to break the bottom-hole rock is. Furthermore, the maximum principal stress of the bottom-hole increases as the mud pressure, well depth and temperature difference increase. The bottom-hole rock can be divided into three main regions according to the stress state, namely a) three directions tensile area, b) two directions compression areas and c) three directions compression area, which are classified as a) easy, b) normal and c) hard, respectively, for the corresponding fragmentation degree of difficulty. The main contribution of this paper is that it presents for the first time a thorough study of the effect of related factors, including stress distribution and temperature, on the bottom-hole rock fracture rather than the well wall, using a thermo-poroelastoplasticity model.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.24 no.7
• /
• pp.914-924
• /
• 2020

In this study we developed artificial network generation model, which can generate on-line social network. The suggested model can represent not only scale-free and small-world properties, but also can produce networks with various values of topological characteristics through controlling two input parameters. For this purpose, two parameter K and P are introduced, K for controlling the strength of preferential attachment and P for controlling clustering coefficient. It is found out on-line social network can be generated with the combinations of K(0~10) and P(0.3~0.5) or K=0 and P=0.9. Under these combinations of P and K small-world and scale-free properties are well represented. Node degree distribution follows power-law. Clustering coefficients are between 0.130 and 0.238, and average shortest path distance between 5.641 and 5.985. It is also found that on-line social network properties are maintained as network node size increases from 5,000 to 10,000.

• Korean Journal of Metals and Materials
• /
• v.49 no.6
• /
• pp.474-487
• /
• 2011

Bars of OFHC Cu with the diameter of 45 mm were processed by equal channel angular pressing up to 16 passes via route $B_c$, and homogeneity of their microstructures and mechanical properties was examined at every four passes which develop the equiaxed ultrafine grains. In general, overall hardness, yield strength and tensile strength increased by 3, 7, and 2 times respectively compared with those of unECAPed sample. Cross-sectional hardness exhibited a concentric distribution. Hardness was the highest at the center of bar and it decreased gradually from center to surface. After 16 passes, overall hardness decreased due to recovery and partial recrystallization. Regardless of the number of passage, yield strength and tensile strength were quite uniform at all positions, but elongation showed some degree of scattering. At 4 passes, coarse and ultrafine grains coexisted at all positions. After 4 passes, uniform equiaxed ultrafine grains were obtained at the center, while uniform elongated ultrafine grains were manifested at the upper half position. At the lower half position, grains were equiaxed but its size were inhomogeneous. It was found that inhomogeneity of grain morphology and grain size distribution at different positions are to be attributed to scattering in elongation but they did not affect strength. The present results reveal the high potential of practical application of equal channel angular pressing on fabrication of large-sized ultrafine grained bars with quite homogeneous mechanical properties.

• Journal of radiological science and technology
• /
• v.44 no.3
• /
• pp.225-229
• /
• 2021

The digital image such as medical X-ray and nuclear medicine field mainly contains noise distribution. The noise degree in image degrades image quality. That is why, the noise reduction algorithm is efficient for medical image field. In this study, we confirmed effectiveness of application for median modified Wiener filter (MMWF) algorithm for noise reduction in PET/MR image compared with median filter image, which is used as conventional noise redcution algorithm. The Jaszczak PET phantom was used by using 18F solution and filled with NaCl+NiSO4 fluids. In addition, the radioactivity ratio between background and six spheres in the phantom is maintained to 1:8. In order to mimic noise distribution in the image, we applied Gaussian noise using MATLAB software. To evlauate image quality, the contrast to noise ratio (CNR) and coefficient of variation (COV) were used. According to the results, compared with noise image and images with MMWF algorithm, the image with MMWF algorithm is increased approximately 33.2% for CNR result, decreased approximately 79.3% for COV result. In conclusion, we proved usefulness of MMWF algorithm in the PET/MR images.

• Journal of Korean Society of Water and Wastewater
• /
• v.35 no.6
• /
• pp.389-403
• /
• 2021

In this study, dual drainage system based runoff model was established for W-drainage area in G-si, and considering the various rainfall characteristics determined using Huff and Mononobe methods, the degree of flooding in the target area was analyzed and the risk was compared and analyzed through the risk matrix method. As a result, the Monobe method compared to the Huff method was analyzed to be suitable analysis for flooding of recent heavy rain, and the validity of the dynamic risk assessment considering the weight of the occurrence probability as the return period was verified through the risk matrix-based analysis. However, since the definition and estimating criteria of the flood risk matrix proposed in this study are based on the return period for extreme rainfall and the depth of flooding according to the results of applying the dual drainage model, there is a limitation in that it is difficult to consider the main factors which are direct impact on inland flooding such as city maintenance and life protection functions. In the future, if various factors affecting inland flood damage are reflected in addition to the amount of flood damage, the flood risk matrix concept proposed in this study can be used as basic information for preparation and prevention of inland flooding, as well as it is judged that it can be considered as a major evaluation item in the selection of the priority management area for sewage maintenance for countermeasures against inland flooding.

• Journal of Acupuncture Research
• /
• v.40 no.1
• /
• pp.35-43
• /
• 2023

Background: This study aimed to examine the effect of Scutellaria baicalensis extract (SBE) on ameliorating pain response and inflammation in an animal model. Methods: The effects of SBE on joint inflammation-induced rats and pain writhing response were measured. In rats with monosodium iodoacetate (MIA)-induced knee osteoarthritis (OA), the weight-bearing distribution of the hind legs was measured, the actual joint condition was visually confirmed, and serum cytokines were extracted from whole blood and measured. In addition, the acetic acid-induced pain was measured by the number of abdominal wall contractions and writhing responses. Results: 1. The weight-bearing distribution of the hind limbs of the SBE group was remarkably improved compared with that of the control group 7 days after MIA treatment, and the SBE 300 group was improved similarly to that of the indomethacin group. 2. Cartilage erosion was significantly recovered in the SBE and indomethacin groups, and the degree of healing of cartilage erosion by SBE was similar to that by indomethacin. 3. The serum levels of cytokines interleukin-1β, tumor necrosis factor-α, and interleukin-6 were significantly decreased in the SBE group compared with that in the control group, and the SBE 300 group had reduced levels of cytokines similar to the indomethacin group. 4. As regards acetic acid-induced writhing response, the number of writhes was significantly reduced in the SBE and ibuprofen groups, and the SBE 600 group had fewer writhes than the ibuprofen group. Conclusion: SBE significantly improves knee OA and pain and is expected to show similar therapeutic effects to indomethacin and ibuprofen.

• Asia-Pacific Journal of Business
• /
• v.14 no.1
• /
• pp.341-350
• /
• 2023

Purpose - How are gains from trade distributed between countries when economic integration is achieved through free trade? The purpose of this paper is to answer this question. Design/methodology/approach - This study attempts to address the issue of distribution of trade gains between participating countries following economic integration in terms of positive economics. The analysis is therefore based on a theoretical methodology. Findings - First, commodity prices fall and consumer surplus increases in both large and small countries. Second, when economic integration into free trade is achieved, gains from trade always exist in small countries. However, the size of trade gains depends on the degree of difference from the market size of the partner country, the large country. However, the size of the gains from trade depends on the extent of difference between the market size of the large country. If the market size of a large country is much larger and there is a large difference, trade gains will be very large, whereas if the market size is similar, profits of domestic firm will decrease. Therefore, in that case, the size of the gains from trade becomes relatively small because only the gains from exchange exists. On the other hand, in a large country with a large market size, there is a possibility of trade gains only when the market size is similar to that of a small country, which is a trading partner. However, if there is a large difference in market size, the decrease in profits of domestic firm is relatively larger than the increase in consumer surplus due to trade, and rather, a trade loss occurs. Research implications or Originality - Our analysis contributes to filling the gaps in the literature regarding the distribution of gains from trade, and from a policy point of view, it is meaningful in examining the impact of market size, an important variable considered in regional economic integration of countries.

• Food Science of Animal Resources
• /
• v.42 no.2
• /
• pp.266-279
• /
• 2022

This study was conducted to evaluate the proteolysis trends and change in meat quality during 10 days of cold storage in duck M. pectoralis major (PM) and M. iliotibialis (IL). Duck IL had a higher pH and greater degree of lightness but lower cooking loss than PM (p<0.05). During the 10-day cold storage, the pH value of PM declined significantly (p<0.05), while the meat quality traits of IL were not affected by cold storage (p>0.05). In PM, the redness increased from day 1 to day 5, while cooking loss was lower on day 10 compared to day 5 (p<0.05). There were no significant differences in the activities of cathepsin B and proteasome 20S during cold storage (p>0.05). The activity of calpains declined gradually during 10 days of storage (p<0.05), and the activity of calpains in PM was higher than that in IL (p<0.05). A total of 5,155 peptides were detected and derived from 34 proteins of duck PM muscle, whereas 4,222 peptides derived from 32 proteins were detected from duck IL muscle. Duck PM muscle was composed only of fast type of muscle fiber, whereas IL muscle was composed of both slow and fast types. The proteins responsible for glycolysis or myofibrillar proteins were closely related to changes in meat color or water-holding capacity during cold storage. These results suggest that changes in meat quality characteristics during cold storage are closely related to protein degradation, which is also related to the distribution of muscle fiber types.

• Nuclear Engineering and Technology
• /
• v.55 no.11
• /
• pp.3996-4001
• /
• 2023

The High-flux Advanced Neutron Application Reactor (HANARO) produces radioisotopes (RIs) (¹³¹I, ¹⁹²Ir, etc.) through neutron irradiation on various RI production targets. Among them, ¹⁷⁷Lu and ¹⁶⁶Ho are particularly promising owing to their theranostic characteristics that facilitate simultaneous diagnosis and treatment. Prior to neutron irradiation, evaluating the nuclear heating of the RI production target is essential for ensuring the thermal-hydraulic safety of HANARO. In this study, the feasibility of producing ¹⁷⁷Lu and ¹⁶⁶Ho using irradiation holes of HANARO was investigated in terms of thermal-hydraulic safety. The nuclear heating rates of the RI production target by prompt and delayed radiation were calculated using MCNP6. The calculated nuclear heating rates were used as an input parameter in COMSOL Multiphysics to obtain the temperature distribution in an irradiation hole. The degree of temperature increase of the ¹⁷⁷Lu and ¹⁶⁶Ho production targets satisfied the safety criteria of HANARO. The nuclear heating rates and temperature distribution obtained through the in silico study are expected to provide valuable insight into the production of ¹⁷⁷Lu and ¹⁶⁶Ho using HANARO.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.20 no.3
• /
• pp.252-261
• /
• 2018

This study was conducted to develop a method to generate daily maximum and minimum temperatures using monthly data. We analyzed 30-year daily weather data of the 23 meteorological stations in South Korea and elucidated the parameters for predicting annual trend (center value ($\hat{U}$), amplitude (C), deviation (T)) and daily fluctuation (A, B) of daily maximum and minimum temperature. We use national average values for C, T, A and B parameters, but the center value is derived from the annual average data on each stations. First, daily weather data were generated according to the occurrence of rainfall, then calibrated using monthly data, and finally, daily maximum and minimum daily temperatures were generated. With this method, we could generate daily weather data with more than 95% similar distribution to recorded data for all 23 stations. In addition, this method was able to generate Growing Degree Day(GDD) similar to the past data, and it could be applied to areas not subject to survey. This method is useful for generating daily data in case of having monthly data such as climate change scenarios.