• Transactions of Materials Processing
• /
• v.9 no.2
• /
• pp.159-164
• /
• 2000

In this paper, a computer simulation technique for the forging process having a floating die is presented. The penalty rigid-plastic finite element method is employed together with an iteratively force-balancing method, in which the convergence is achieved when the floating die part is in force equilibrium within the user-specified tolerance. The force balance is controled by adjusting the velocity of the floating die in an automatic manner. An application example of a three-stage cold forging process is given.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 1999.03b
• /
• pp.103-107
• /
• 1999

In this paper, a computer simulation technique for the forging process having a floating die is presented. The penalty rigid-plastic finite element method is employed together with an iteratively force-balancing method, in which the convergence is achieved when the floating die part is in force equilibrium within the user-specified tolerance. The force balance is controled by adjusting the velocity of the floating die in an automatic manner. An application example of a three-stage cold forging process is given.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.16 no.1
• /
• pp.123-136
• /
• 2018

The objective of this study is to propose a new methodology to fabricate a reliable engineering-scale buffer block, which shows homogeneous and uniform distribution in buffer block density, for in-situ experiments. In this study, for the first time in Korea, floating die press and CIP (Cold Isostatic Press) are applied for the manufacture of an engineering-scale bentonite buffer. The optimized condition and field applicability are also evaluated with respect to the method of manufacturing the buffer blocks. It is found that the standard deviation of the densities obtained decreases noticeably and that the average dry density increases slightly. In addition, buffer size is reduced by about 5% at the same time. Through the test production, it is indicated that the stress release phenomenon decreases after the application of the CIP method, which leads to a reduction in crack generation on the surface of the buffer blocks over time. Therefore, it is confirmed that the production of homogeneous buffer blocks on industrial scale is possible using the method suggested in this study, and that the produced blocks also meet the design conditions for dry density of buffer blocks in the AKRS (Advanced Korea Reference Disposal System of HLW).

• Journal of the Korean Geotechnical Society
• /
• v.38 no.12
• /
• pp.113-123
• /
• 2022

The required density relationship according to the press pressure of the floating die method and the homogeneity of the density distribution in the buffer block was evaluated to analyze the manufacturing characteristics of engineering scale bentonite-sand buffer blocks. In addition, the thermal conductivity was measured and compared with that of the pure bentonite buffer block to evaluate the level of thermal conductivity performance improvement of the bentonite-sand buffer material. As a result, it was confirmed that the standard deviation of dry density decreased to 0.011 and showed a homogeneous density distribution under the condition of press pressure greater than 400 kg/cm². Furthermore, as a result of the thermal conductivity test, the thermal conductivity of the buffer with optimum moisture content conditions was 1.345 and 1.261 W/(m·K) under the press pressure of 400 and 600 kg/cm², respectively. It increased by 16.1% and 11.0% compared to the pure bentonite buffer material. Based on the results of this study, it is judged that it can be used as fundamental data for manufacturing a homogeneous bentonite-sand buffer block on an engineering scale.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.14 no.6
• /
• pp.57-62
• /
• 2015

A large variety of pipe flanges are required in the marine and construction industry. Pipe flanges are usually welded or screwed to the pipe end and are connected with bolts. This approach is very simple and has been widely used for a long time; however, it results in high development costs and low productivity, and the products made through this approach usually have safety problems in the welding area. In this research, a new approach for forming pipe flanges based on cold forging and the floating die concept is presented. This innovative approach increases the effectiveness of the material usage and saves time and costs compared with the conventional welding method. To ensure the dimensional accuracy of the final product, finite element analysis (FEA) was carried out to simulate the process of cold forging, and orthogonal experiment methods were used to investigate the influence of four manufacturing factors (stroke of distance, pin die angle, forming of pipe diameter, and speed of the die) and predict the best combination of them. The manufacturing factors were obtained through numerical and experimental studies, which show that the approach is very useful and effective for the forming of pipe flanges and could be widely used in the future.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.3
• /
• pp.563-569
• /
• 2007

As the mobile communication and the semiconductor technology is improved continuously, mobile contents such as the multimedia service and the 2D/3D graphics which require high level graphics are serviced recently. Mobile chips should consume small die area and low power. In this paper, we design a truncated floating-point multiplier that is useful for the 2D/3D vector graphics in mobile devices. The truncated multiplier is based on the radix-4 Booth's encoding algorithm and a truncation algorithm is used to achieve small area and low power. The average percent error of the multiplier is as small as 0.00003% and neglectable for mobile applications. The synthesis result using 0.35um CMOS cell library shows that the number of gates for the truncated multiplier is only 33.8 percent of the conventional radix-4 Booth's multiplier.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 1993.06a
• /
• pp.1394-1397
• /
• 1993

A Fuzzy Microprocessor(FMP) is presented, which is suitable for real-time control applications. The features include high speed inference of maximum 114K FLIPS at 20MHz system clocks, capability of up to 128-rule construction, and handing of 8 input variables with 8-bit resolution. In order to realize these features, the fuzzifier circuit and the processing element(PE) are well optimized for LSI implementation. The chip fabricated in 1.2$\mu\textrm{m}$ CMOS technology contains 71K transistors in 82.8 $\textrm{mm}^2$ die size and is packaged in 100-pin plastic QFP.

• Development and Reproduction
• /
• v.22 no.3
• /
• pp.289-295
• /
• 2018

Large quantity of eggs fail to be fertilized and many of fertilized eggs are unable to hatch in the eel, Anguilla japonica. Larvae of eel absorb egg yolk up to 8 days after hatching but the majority of hatched larvae die before they reach the stage of first feeding in this species. Genes of key enzymes for yolk processing (cathepsin B, D, L and lipoprotein lipase - abbreviated as ctsb, ctsd, ctsl and lpl, respectively) could be associated with egg quality. In this study, we investigated differences in the expression of these genes between floating eggs and sinking eggs, and also the relationship between the gene expressions of the enzymes and fertilization rates in the fertilized eggs obtained from artificially matured female eels. Expressions of yolk processing enzyme genes did not show significant difference between floating and sinking egg groups. Expression of ctsb decreased when fertilization rate was high. Expression of ctsd, ctsl and lpl, however, did not show any significant differences. These results suggest that ctsb expression could be an indicator of egg quality, and that some proteins prone to be digested by ctsb could be very important in the process of fertilization and normal cleavage in this species. Further study should identify these critical proteins to improve our understanding on the quality of fish eggs.

• Journal of environmental and Sanitary engineering
• /
• v.14 no.4
• /
• pp.77-84
• /
• 1999

Most river quality problems are generated by pollutants which are discharged into the river as a consequence of human activities. And eutrophication occurs when water is over enriched with nutrients, principally nitrate and phosphate. Both these nutrients are found in many waste products, especially sewage even when the waste is treated. Eutrophication is concerned in lakes, but it also causes problems in river. Wide growth of Phytoplankton in rivers, leads to blockage of channels, but the main concern is deoxygenation because of the increase in plant life's demand for oxygen in revers. Fish, plant and animals die due to lack of oxygen. The increase of algae floating on the tops of water looks ugly and has attracted public attention and concern in recent years. One way of controlling eutrophication is to restrict the amount of waste carrying nitrate or phosphate from entering the water in the first place. another way is to remove it from the water after it has been entered. This study was carried out to investigate on the trophic state, nutrients and Chlorophyll-a concentration in the Han River. The results were as follows:1. Concentrations of total nitrogen were 2.208~9.221(5.133)mg/$\ell$2. Concentrations of total phosphate were 0.045~0.614(0.195)mg/$\ell$3. Chlorophyll-a concentration were $0.0-25.3(9.6)mg/m^3$.4. The correlation coefficient between T-P and Chlorophyll-a concentration was r=-0.856 at Sungsan sampling site.5. The correlation coefficient was r=-0.578~-0.767, between Paldang Dam outflow and Chlorophyll-a concentration at all sampling sites.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.4
• /
• pp.2643-2647
• /
• 2013

Background: Despite anti-smoking campaigns, smoking prevalence among Thai males aged 30 or older is high, at around 50%. The purpose of this study was to determine the relationship between smoking and mortality in a rural Thai community. Materials and Methods: Subjects enrolled into the Khon Kaen cohort study between 1990 and 2001 were followed up for their vital status until $16^{th}$ March 2012. The death resource was from the Bureau of Policy and Strategy, Ministry of Interior, Thailand. A Cox proportional hazards model was used to analyse the association between smoking and death, controlling for age, education level and alcohol drinking, and confidence intervals were calculated using the floating risk method. Results: The study recruited 5,962 male subjects, of whom 1,396 died during a median 13.5 years of follow-up. Current smokers were more likely to die than never smokers after controlling for age, education level and alcohol drinking (HR, 95%CI: 1.41, 1.32-1.51), and the excess mortality was greatest for lung cancer (HR, 95%CI: 3.51, 2.65-4.66). However, there was no increased risk with increasing dose of tobacco, and no difference in risk between smokers of yamuan (hand-rolled cigarettes) and manufactured tobacco. Conclusion: Mortality from cancer, particularly lung cancer, and from all causes combined is dependent on smoking status among men in rural Thailand, but the relative risks are lower than have been reported from studies in high income countries, where the tobacco epidemic is more established.