• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1049-1078
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• 2021

The review summarizes the published data on the widely applied electron-beam, laser-beam, as well as resistance upset, projection, and spot welding of zirconium alloys for nuclear applications. It provides the results of their analysis to identify common patterns in this area. Great attention has been paid to the quality requirements, the edge preparation, up-to-date equipment, process parameters, as well as post-weld treatment and processing. Also, quality control and weld repair methods have been mentioned. Finally, conclusions have been drawn about a significant gap between the capabilities of advanced welding equipment to control the microstructure and, accordingly, the properties of welded joints of the zirconium alloys and existing algorithms that enable to realize them in the nuclear industry. Considering the ever-increasing demands on the high-burnup accident tolerant nuclear fuel assemblies, great efforts should be focused on the improving the welding procedures by implementing predefined heat input cycles. However, a lot of research is required, since the number of possible combinations of the zirconium alloys, designs and dimensions of the joints dramatically exceeds the quantity of published results on the effect of the welding parameters on the properties of the welds.

• Journal of Ocean Engineering and Technology
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• v.38 no.1
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• pp.30-42
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• 2024

This study examined the jack-up spudcan penetration for a new type of offshore wind substructure newly proposed using the jack-up concept to reduce construction costs. The jack-up spudcan for offshore wind turbines should be designed to penetrate a stable soil layer capable of supporting operational loads. This study evaluated multi-layered soil conditions using centrifuge tests: loose sand over clay and loose sand-clay-dense sand. The penetration resistance profiles of spudcan recorded at the centrifuge tests were compared with the ISO and InSafeJIP methods. In the tests, a spudcan punch-through effect slightly emerged under the sand-over-clay condition, and a spudcan squeezing effect occurred in the clay-over-sand layer. On the other hand, these two effects were not critically predicted using the ISO method, and the InSafeJIP result predicted only punch-through failure. Nevertheless, ISO and InSafeJIP methods were well-matched under the conditions of the clay layer beneath the sand and the penetration resistance profiles at the clay layer of centrifuge tests. Therefore, the ISO and InSafeJIP methods well predict the punch-through effect at the clay layer but have limitations for penetration resistance predictions at shallow depths and strong stratum soil below a weak layer.

• Journal of Korean Neurosurgical Society
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• v.48 no.4
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• pp.319-324
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• 2010

Objective : The aim of this study was to analyze the correlation between thromboembolic complications and anti platelet drugs before and after neurointervention. Methods : Blood samples and radiographic data of patients who received a neurointervention (coil embolization, stent placement or both) were collected prospectively. Rapid platelet function assay-aspirin (RPFA-ASA) was used to calculate aspirin resistance in aspirin reaction units (ARU). For clopidogrel resistance, a P2Y12 assay was used to analyze the percentage of platelet inhibition. ARU > 550 and platelet inhibition < 40% were defined as aspirin and clopidogrel resistance, respectively. Results : Both aspirin and clopidogrel oral pills were administered in fifty-three patients before and after neurointerventional procedures. The mean resistance values of all patients were 484 ARU and < 39%. Ten (17.0%) of 53 patients showed resistance to aspirin with an average of 597 ARU, and 33 (62.3%) of 53 patients showed resistance to clopidogrel with an average of < 26%. Ten patients demonstrated resistance to both drugs, 5 of which suffered a thromboembolic complication after neurointervention (mean values : 640 ARU and platelet inhibition < 23%). Diabetic patients and patients with hypercholesterolemia displayed mean aspirin resistances of 513.7 and 501.8 ARU, and mean clopidogrel resistances of < 33.8% and < 40.7%, respectively. Conclusion : Identifying individuals with poor platelet inhibition using standard regimens is of great clinical importance and may help prevent cerebral ischemic events in the future. Neurointerventional research should focus on ideal doses, timing, choices, safety, and reliable measurements of anti platelet drug therapy, as well as confirming the clinical relevance of aggregometry in cerebrovascular patients.

• Journal of Power System Engineering
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• v.20 no.5
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• pp.29-36
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• 2016

Aluminum alloys have been widely used in engine materials, cold & hot-water storage vessels and piping etc., Furthermore, the aluminum alloy of AC8A have been widely used in mold casting material of engine piston for various vehicles because of its properties of temperature, wear and corrosion resistance. Therefore, it is considered that evaluation of corrosion resistance as well as wear resistance of AC8A material is also important to improve its property and to prolong its lifetime. In previous paper, the effect of solution($510^{\circ}C$:4hrs) and tempering($190^{\circ}C$: 16, 24, and 36 hrs)heat treatments to corrosion resistance and hardness were investigated using electrochemical method. In this study, in order to examine completely the effect of the tempering hours to hardness variation and corrosion resistance, the results of solution($510^{\circ}C$:4hrs) and tempering($190^{\circ}C$: 2, 4, 8 and 12hrs)heat treatments to hardness and corrosion resistance were investigated using electrochemical method. The hardness decreased with solution heat treatment compared to mold casting condition, but its value increased with tempering heat treatment. Furthermore, the corrosion resistance increased with decreasing of the hardness, and decreased with increasing of the hardness reversely. And the tempering heat treatment temperature at $190^{\circ}C$ for 8 hrs exhibited the highest value of the hardness and also indicated the highest corrosion current density. However, the values of hardness and corrosion current density was again increasingly decreased with increasing of tempering hours than 8 hrs, Consequently, it is suggested that decision of the optimum. tempering hours is very important to improve the corrosion or wear resistance.

• Korean Journal of Food Science and Technology
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• v.50 no.6
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• pp.581-586
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• 2018

Enterococcus spp. have been considered major indicator organisms for antibiotic resistance due to their ability to easily acquire and to harbor antibiotic resistance. In this study, Enterococcus spp. were isolated from 174 retail fresh-cut products (fresh vegetable salads, microgreens, and sprouts) in Korea. Among the 20 Enterococcus isolates obtained, 18 (90.0%) were Enterococcus faecalis and 2 (10.0%) were Enterococcus faecium. The patterns of antibiotic resistance against nine antimicrobials were analyzed. Most of the isolates (85.0%) were resistant to quinupristin/dalfopristin, 40.0% and 50.0% of the isolates showed intermediate resistance to two critically important antimicrobials for human medicine, ciprofloxacin and erythromycin, respectively. Vancomycin-resistant enterococci were not detected in this study. Given the importance of antimicrobial resistance of enterococci in food safety as well as in public health, our results regarding the occurrence (level of contamination) and antimicrobial resistance of Enterococcus spp. could provide useful information that aids the risk analysis of antibiotic resistance.

• Journal of the Daesoon Academy of Sciences
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• v.22
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• pp.277-316
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• 2014

Many ideas which have appear in human history ought to be fruits of the relevant time, however they sometimes reveal new meaning. Daesoon idea is like that, and anarchism also has been resurgent today according to the demand of the time. Both ideas aim at an ideal society. They are not codes of conduct by specific ideology, but are the spirit of resistance against all kinds of oppression, i.e. which began from human nature. Anarchism refuses intellectual revolution theory or idea, but it wants only the life of human nature. Therefore, in spite of the diversity of its historic type, anarchism is in the same discussion as idealism e.g. religion, politics, etc. which have seek the essence of human life. Daesoon idea, as well, begins from religious idealism, it kindles the same discussion as anarchism. Particularly, anarchism is receiving attention with its spirituality of the new century. If so, it will be a critical help for the development of Daesoon idea to consider such newness through a conversation with anarchism. A comparison between Daesoon idea and anarchism is mainly a conversation about the ideology of ideal society. The researcher intended to investigate the viewpoint of anarchism in terms of comparing its personality, society and nation with Daesun idea, though it was not easy work since the ideological genealogy of anarchism is various. Both of them have a mental attitude, i.e. 'essential resistance', on the basis of such introspection. The spirit of resistance is an essence of man and the right of resistance is a basic human rights that insist the dignity of man. When the right of resistance reaches the essence of human life, it becomes an ideal thought and religion. Also, the ideal can be finally realized when the spirit of resistance becomes the power of practice by actualizing it as the right of resistance.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.263-266
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• 2002

Rises of temperature and resistance are observed in HTS tapes under over current condition. In this paper, we measured HTS tapes properties under low-over current condition with a little temperature rise as well as high-over current condition with a large temperature rise. According to the results of measurement, rises of temperature and resistance strongly depend on insulation level and duration of over current condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.6
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• pp.216-222
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• 1996

This paper presents a computational technique to predict roof crush resistance in early design stage of passenger car development. This technique use a simple F.E. model with nonlinear spring elements which represent plastic hinge behavior at weak areas. By assuming actual sections as equivalent simple sections, maximum bending moments which weak areas in major members can stand are theoretically calculated. Results from prediction of roof crush resistance are correlated well with test results.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.04a
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• pp.152-157
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• 1994

Due to the recent shortage of river sand resulting from a rapid growth of concrete construction, sea sand is increasingly used in stead. It is, however, well noted that non-washed sea sand used in reinforced concrete causes to corrode reinforcing steel and to incur cracks in concrete, and thus eventually result in damage to concrete. In this study, therefore, measeres that increase the quality of concrete were used to protect the reinforcing steel against corrosion in reinforced concrete construction, and then the corrosion resistance of reinforcing steel compared and analyzed from low quality concrete to high quality concrete.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.04a
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• pp.90-95
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• 1990

It is widely recognized that the strengths of reinforced concrete members have random characteristics due to the variability of the mechanical properties of concrete and steel, the dimensional error as well as incorrect placement of reinforcing bars. Statistical models of the variabilities of strengths of reinforced concrete members, therefore, need to be developed to evaluate the safety level implied in current practices. Based on the probabilistic models of basic factors affecting the R.C. member strengths, in this study, the probabilistic characteristics of member resistance have been studied through Monte Carlo simulation.