Pyroprocessing technology has emerged as a viable alternative for the treatment of metal/oxide used fuel within the nuclear fuel cycle. This innovative approach involves an oxide reduction process wherein spent fuel in oxide form is placed within a cathode basket immersed in a molten LiCl-Li2O salt operating at 923 K. The chemical reduction of these oxide materials into their metallic counterparts occurs through a reaction with Li metal, which is electrochemically deposited onto the cathode. However, during process, the generation of Li2O within the fuel basket is inevitable, and due to the limited reduction efficiency, a significant portion of rare earth oxides (REOx) remains in their oxide state. The presence of these impurities, specifically Li2O and REOx, necessitates their transfer into the electrorefining system, leading to several challenges. Both Li2O and REOx exhibit reactivity with UCl3, the primary electrolyte within the electrorefining system, causing a continuous reduction in UCl3 concentration throughout the process. Furthermore, the formation of fine UO2 powder within the salt system, resulting from chemical reactions, poses a potential long-term operational and safety concern within the electrorefining process.Various techniques have been developed to address the issue of UO2 fine particle removal from the salt, utilizing both chemical and mechanical methods. However, it is crucial that these methods do not interfere with the core pyroprocessing procedure. This study aims to investigate the impact of Li2O and REOx introduced from the electrolytic reduction process on the electrorefining system. Additionally, we propose a method to effectively eliminate the generated UO2 fine powder, thereby enhancing the long-term operational stability of the electrorefining process. The efficiency of this proposed solution in removing oxidized powder has been confirmed through laboratory-scale testing, and we will provide a comprehensive discussion of the detailed results.
소변검사 전 냉/해동 반복과 해동 과정에 따라 대표적인 임상 화학검사 측정값의 변화를 확인 함으로써 소변검사의 안정성과 품질 개선방안을 모색하고자 하였다. 조사 대상자는 모두 건강한 남성 10명이었으며 이들의 소변 검체를 이용하여 냉/해동 안정성(freeze and thaw stability) 실험을 진행하였다. Micro-albumin과 Amylase의 경우 시간이 경과 됨에 따라 37℃에서 는 통계적 유의성은 없었으나, 42℃와 60℃에서는 시간의 경과에 따른 결과가 통계적으로 유의한 변동 이 있었고, BUN, Creatinine, Uric acid와 Glucose에서는 통계적으로 유의한 변동이 있었다. Long term의 안정성 결과, 7일이 지난 후에는 Glucose의 변이는 증가하였고, 60℃에서는 Amylase가 감 소하는 양상을 보였다. Glucose와 Amylase의 경우 시간의 경과에 따른 결과가 통계적으로 유의한 변동 이 있었다. 신뢰성 있는 검사결과를 얻기 위해서는 소변 시료의 채취, 보관 및 저장 등을 비롯한 요검사 의 정확한 표준화가 필요하며 생체 물질별 안정성 확보를 위한 조건들의 체계적 연구가 필요하다.
The high-temperature stability of YSZ specimens fabricated by die pressure and cold isostatic press (CIP) is investigated in CaCl2-CaF2-CaO molten salt at 1,150 °C. The experimental results are as follows: green density 46.7 % and 50.9 %; sintering density 93.3 % and 99.3 % for die press and CIP, respectively. YSZ foremd by CIP exhibits higher stability than YSZ formed by die press due to denseness dependency after high-temperature stability test. YSZ shows peaks mainly attributed to CaZrO3, with a small t-ZrO2 peak, unlike the high-intensity tetragonal-ZrO2 (t-ZrO2) peak observed for the asreceived specimen. The t-ZrO2 phase of YSZ is likely stabilized by Y2O3, and the leaching of Y2O3 results in phase transformation from t-ZrO2 to m-ZrO2. CaZrO3 likely forms from the reaction between CaO and m-ZrO2. As the exposure time increases, more CaZrO3 is observed in the internal region of YSZ, which could be attributed to the inward diffusion of molten salt and outward diffusion of the stabilizer (Y2O3) through the pores. This results in greater susceptibility to phase transformation and CaZrO3 formation. To use SOM anodes for the electroreduction of various metals, YSZ stability must be improved by adjusting the high-density in the forming process.
Saline water electrolysis is an electrochemical process to produce valued chemicals by applying electric power. Perfluorinated sulfonic acid (PFSA) ionomers have been used as polymer electrolyte membrane (PEM) materials owing to their high sodium ion selectivity and barrier properties. However, sulfonic acid groups in PFSA ionomers are chemically decomposed under a basic catholyte condition, which makes the PEM materials lose their ionic selectivity and Faraday efficiency. In this study, double layered membranes were prepared by anchoring cross-linked hydrocarbon ionomers, as a protection layer to catholyte atmosphere, into the water channels, particularly, located at around the surface of a PFSA membrane. Here, each monomer results in the identical chemical architecture and different free volume content when polymerized.
SUS hexagonal bar has been widely used to make many kinds of hexagonal bolt/nuts and fittings. Peeling machine is used to make lustrous and clean surface of SUS circular bar in order to remove rust and impurities from surface of raw SUS circular bar. Similarly, roll unit system is used to make SUS hexagonal bar from SUS circular bar with lustrous and clean surface. Roll unit system is mainly divided into two parts ; one is roll unit and the other is mold frame. The purpose of this study was to evaluate the structural stability of mold frame supporting roll unit with numerical analysis. As the numerical analysis result, higher structural stability was gradually shown in order of models 4, 2, 3 and 1. It was considered that the structural stability of this study was influenced by the decrease of mold frame size, especially height decrease.
With the development of information technology, the market situation is changing more rapidly than ever. The change is most rapid in the preferences and lifestyle of consumers. For companies to survive in such an environment, it is indispensable to develop innovative and competitive new products by better understanding the needs of consumers. Any novel and meaningful idea of a new product basically originates from knowledge, which plays an important role in the performance of new products because it is the most valuable asset for a business entity. In this study, the author considers the knowledge sharing process as a dynamic aspect based on the term “knowledge,” carrying a static meaning as used in the existing research. The nature of the knowledge sharing process pertaining to new product development has been largely divided into three terms and then re-established. The author focuses on a new product development team as the subject of sharing and providing knowledge on new products, and regards the solution to problems that may arise in the development process as the stability of the team. The moderating effect was examined by the relationship between the type of knowledge sharing process and the outcome of the new product with the variable of team stability. The results indicate that the convergence and similarity of the knowledge sharing process affect new product performance as positive variables, whereas the tacitness of the knowledge sharing process does not lead to a significant result in terms of performance of new products. This study also shows that the stability of the team has a positively direct effect on the outcome of the new product. Thus, the convergence process of various kinds of knowledge positively affects the diversity and innovation of new product concepts. Moreover, the same recognition area or shared goal awareness and sense of responsibility play important roles in the performance of the new product. The moderating effect of team stability between the type of knowledge sharing process and new product performance is described in the convergence and tacitness of the knowledge sharing process. In the process of merging existing knowledge with new knowledge or sharing embedded knowledge in the members with, the activity wherein the members of the NPD team communicate and collaborate with each other over a long period of time will provide opportunity to improve the performance of the new product. The purpose of this paper is to examine the relationship between the type of knowledge sharing process, the stability of the team, and new product performance. Academic and managerial implications and the directions for future research are discussed as well.
CE RCD (Recreational Craft Directive) is a certification for the design and construction of small vessels, including pleasure yachts, which are widely used not only in the countries within the European Union, but also in Japan and Southeast Asia. Recently, South Korean leisure craft shipyards have developed interest in exporting to foreign leisure craft markets such as Europe; however, they have encountered difficulties because of the CE RCD regulations, which are relatively complex and difficult to understand. The requirements for buoyancy and stability, which are essential properties that must be understood within the early stage of ship design, are defined based on ISO 12217. However, preparing this assessment according to ship classification regulations is an exceedingly complex task, even with knowledge of naval architecture. In this research, we have developed design support tools to systematically support assessments and preemptively define design information so that buoyancy and stability assessments based on ISO 12217 can be systematically prepared. Our research results were applied to actual examples of yacht design to confirm validity. We believe that the improved yacht design process presented in this research can act as a foundational reference for enhancing the effectiveness and systematic buoyancy and stability assessments.
Immobilization of anaerobic ammonium oxidizing bacteria has been studied to enhance the biomass retention of the slowly growing bacteria and the process stability. The purpose of this study was to compare the nitrogen removal efficiency of granular and immobilized anammox bacteria with poly vinyl alcohol and alginate. The specific anammox activity of the granular, homoginized and immobilized anammox bacteria were 0.016±0.0002 gN/gVSS/d, 0.011±0.001 gN/gVSS/d and 0.007±0.0005 gN/gVSS/d, respectively. Although the activity decreased to 43.7 % of the original one due to low pH and O2 exposure during the homogination and the immobilization, it was rapidly recovered within 7 days in the following continuous culture. When synthetic T-N concentrations of 100, 200, 400, 800 mg/L were fed, the immobilized anammox bacteria showed higher nitrogen removal efficiencies at all operational conditions than those of granular anammox bacteria. When the sludge retention time was shorten below 30.7 days and the reject water was fed, the nitrite removal efficiency of the granular anammox bacteria dropped to 8 % of the initial value, while that of the immobilized anammox bacteria was maintained over 95 % of the initial one. The immobilization with poly vinyl alcohol and alginate would be a feasible method to improve the performance and stability of the anammox process.
The purpose of this paper was to investigate the effect of a high-energy milling (HEM) process on the particle morphology and the correlation between a thermal treatment and tetragonal/monoclinic nanostructured zirconia powders obtained by a precipitation process. To eliminate chloride residue ions from hydrous zirconia, a modified washing method was used. It was found that the used washing method was effective in removing the chloride from the precipitated gel. In order to investigate the effect of a pre-milling process on the particle morphology of the precipitate, dried Zr(OH)4 was milled using a HEM machine with distilled water. The particle size of the Zr(OH)4 powder exposed to HEM reduced to 100~150 nm, whereas that of fresh Zr(OH)4 powder without a pre-milling process had a large and irregular size of 100 nm~1.5 μm. Additionally, modified heat treatment process was proposed to achieve nano-sized zirconia having a pure monoclinic phase. It was evident that two-step calcining process was effective in perfectly eliminating the tetragonal phase, having a small average particle of ~100 nm with good uniformity compared to the sample calcined by a single-step process, showing a large average particle size of ~300 nm with an irregular particle shape and a broad particle size distribution. The modified method is considered to be a promising process for nano-sized zirconia having a fully monoclinic phase.
The process variables for the manufacture of translucent microemulsion prepared with 2-octyl dodecanol, 12-hydroxy stearic acid cholesteryl , POE(40)HCO and 1,3-butandiol were examined initially (primary emulsion) and following aging for three months. The techniques empolyed in this study were particle size, turbidity, interfacial tension and microfluidizer. Particle size analysis and turbidity measurement to evaluate the emulsion stability were used. It was concluded that the process of the emulsification was an important indicator of the stability of the translucent microemulsion. From the particle size and and turbidity measurement of translucent microemulsion, adding the surfactant to the oil phase before the emulsification was found to be the most important factor for the stability of emulsions. We found that interfacial tension of the adding the surfactant to the oil phase is lower than that of the adding the surfactant to aqueous phase. In spite of hydrophilic surfactant, adding the surfactant to aqueous phase produced inferior emulsion to that to oil phase.
Recently, it is a critical issue for Korea that Metropolitan Landfill site life extension was in crisis contrast for localresidents and local governments. In Europe and Japan, the generation of waste and landfills were suppressed and theyintroduced the MBT facility in order to increase the recycling and energy recovery. In this study, the process of domesticMBT facilities were evaluated by the physical and chemical composition, calorific value and biomass content, the aerobicbiodegradation of biodegradable waste by comparing and analyzing each step through the evaluation. Both organic residuesand inorganic residues carbon content discharged from the MBT analysis, moisture content, calorific value of residues didnot meet solid refuse fuels quality standards. While the biomass content and aerobic biodegradation higher than standardbiodegradable waste landfill in Europe. Biodegradable organic residue selected from domestic solid fuel manufacturingfacility is expected to be able to manage through the biomass content and biological stability analysis. Based on the resultsof future research it is needed to review the criteria and additional landfill energy recovery by incineration residues.