In today’s world, carbon-based materials research is much wider wherein, it requires a lot of processing techniques to manufacture or synthesize. Moreover, the processing methods through which the carbon-based materials are derived from synthetic sources are of high cost. Processing of such hierarchical porous carbon materials (PCMs) was slightly complex and only very few methods render carbon nano-materials (CNMs) with high specific surface area. Once it is processed, which paves a path to versatile applications. CNMs derived from biological sources are widespread and their application spectrum is also very wide. This review focuses on biomass-derived CNMs from various plant sources for its versatile applications. The major thrust areas of energy storage include batteries, super-capacitors, and fuel cells which are described in this article. Meanwhile, the challenges faced during the processing of biomass-derived CNMs and their future prospects are also discussed comprehensively.

Radioactive waste generated during decommissioning of nuclear power plants is classified according to the degree of radioactivity, of which concrete and soil are reclassified, some are discharged, and the rest is recycled. However, the management cost of large amounts of concrete and soil accounts for about 40% of the total waste management cost. In this study, a material that absorbs methyl iodine, a radioactive gas generated from nuclear power plants, was developed by materializing these concrete and soil, and performance evaluation was conducted. A ceramic filter was manufactured by forming and sintering mixed materials using waste concrete, waste soil, and by-products generated in steel mills, and TEDA was attached to the ceramic filter by 5wt% to 20wt% before adsorption performance test. During the deposition process, TEDA was vaporized at 95°C and attached to a ceramic filter, and the amount of TEDA deposition was analyzed using ICP-MS. The adsorption performance test device set experimental conditions based on ASTM-D3808. High purity nitrogen gas, nitrogen gas and methyl iodine mixed gas were used, the supply amount of methyl iodine was 1.75 ppm, the flow rate of gas was 12 m/min, and the supply of water was determined using the vapor pressure value of 30°C and the ideal gas equation to maintain 95%. Gas from the gas collector was sampled to analyze the removal efficiency of methyl iodine, and the amount of methyl iodine detected was measured using a methyl iodine detection tube.

In order to reduce the area of the high-level radioactive waste (HLW) repository, a buffer material with high thermal conductivity is required. This is because if the thermal conductivity of the buffer material is high, the distance between the disposal tunnels and the deposition holes can be reduced. Sand, which is a natural material and has higher thermal conductivity than bentonite, is added to bentonite to develop an enhanced buffer material. For the sand-bentonite mixture, it is important which sand to use and how much to add because an enhanced buffer material should satisfy both hydraulic (H) and mechanical (M) performance criteria while improving thermal conductivity (T). In this study, we would like to show what type of sand and how much sand should be added to develop an enhanced buffer material by adding sand to Gyeongju bentonite, a representative bentonite in Korea. For this purpose, the thermal conductivity, hydraulic conductivity, and swelling pressure of the sand-Gyeongju bentonite mixture according to the sand addition rate were measured. It is more efficient to use silica sand with smaller particles than Jumunjin sand which is a representative sand in Korea as an additive for an enhanced buffer material than using the Jumunjin sand. In order for the sand-Gyeongju bentonite buffer material to satisfy both the hydraulic and mechanical performance criteria as a buffer material while increasing the thermal conductivity, it is judged that the optimum dry density is 1.7 g/cm3 at least and the optimum sand addition rate is 10% at most.

The acoustic emission (AE) method as a passive non-destructive monitoring technique is proposed for real-time monitoring of mechanical degradation in underground structures, such as deep geological disposal of high-level nuclear waste (HLW). This study investigates the low-frequency characteristics of AE signals emitted during the fracturing of meter-scale concrete specimens; uniaxial compression tests (UCT) in a lab scale and Goodman jack (GJ) tests in a 1.3 m-long concrete block were conducted while acquiring the AE signals using low-frequency AE sensors. The results indicate a sharp increase in AE energy emission at approximately 60% and 80% of the yield stresses in the UCT and GJ tests, respectively. The collected AE signals were primarily found in two frequency bands: the 4-28 kHz range and the 56-80 kHz range. High-frequency AE signals were captured more as the stress increased in the GJ tests, which was in contrast to the UCT tests. Furthermore, the AE signals obtained from the Goodman jack tests tended to lower RA values than the UCT results. This study presents unique experimental data with low-frequency AE sensors under different loading conditions, which provides insights into field-scale AE monitoring practices.

For the export of nuclear materials (NM), the NSG guidelines require governmental assurance from the importing State that the NM will be used for peaceful purposes, safeguards and physical protection will be applied, and prior consent will be obtained for retransfer. By providing this assurance, the importing State (recipient) is responsible for fulfilling the obligations required by the exporting States (supplier). If the Nuclear Cooperation Agreement (NCA) has been concluded between the supplier and recipient, it may be replaced by implementing the procedures under the NCA. In the case of NM subject to this obligation, continuous management at the national level is required because prior consent from the supplier may be required for retransfer to a third party under the assurance or may be subject to annual reporting. The obligation swaps are the exchange of obligations of NM without the physical movement of it. Since the physical movement of NM is costly and risky, its obligations are often exchanged for commercial reasons. The basis for obligation swaps is the fungibility and equivalence of NM. The fungibility allows that the inventories of NM need not physically identify the particular NM originally obligated but identify an equivalent quantity of the same isotopic composition. In addition, under the principle of equivalence, even if NM loses its unique physical properties, it can be exchanged by another obligated or nonobligated NM. That is, the principles of equivalence and proportionality allow the comparison of quantities of uranium in different forms. Therefore, it is theoretically possible not only to exchange obligations between NM in same physical form, but also different physical forms of same composition (with the same enrichment), e.g., UO2 powder and its pellets. In U.S., it appears that there are obligation swaps of NM between different enrichment levels, but according to the NCA and its Administrative Arrangement between ROK and U.S., Canada and Australia, the principle of fungibility and equivalence shall not be used to reduce the quality of a quantity of NM. In other words, swaps between NM of different enrichment levels are not allowed under the NCA and AA. However, according to the Supplementary Arrangement between ROK and Canada, the replacement of NM by lower quality NM may only occur where the two States so decide following consultation. The U.S., Canada, and Australia, which are major suppliers of NMs, allow internal obligation swaps within the U.S. and the EU through NCA. The NCA between ROK and these countries does not address whether internal swaps are possible. Since governmental assurance does not impose restrictions on swaps, it can be considered if necessary. Although there is no actual practice of obligation swaps in ROK, research will be necessary regarding the extent to which swaps in ROK should be allowed and the need for government approval or permission.

A bilateral Nuclear Cooperation Agreement (NCA) should define what is subject to the agreement and when. Nuclear Materials (NM) are the subject of NCA with almost all countries, and the definition used in these agreements is borrowed from Article 20 of the IAEA Charter. The IAEA’s definition of NM as consisting of special fissionable material and source material and describes the types of material each contains. In order to control the export of NM under national laws and implement NCA, not only the types of NM but also quantitative criteria are required. This is because controlling small quantities of NM is impossible, unnecessary, and would create excessive administrative burdens. For this reason, the NSG guidelines establish a quantitative threshold of NM requiring control. Nevertheless, no quantitative thresholds have been agreed upon for NM subject to a NCA. Whether NM transferred is subject to the NCA is primarily a matter for the supplier states to determine. The supplier states make the decision based on quantitative criteria defined in their own export control laws. ROK identifies NM that require export licenses by reflecting the same criteria as the NSG guidelines in Foreign Trade Laws and its Notifications. Less than 500 kg of Natural Uranium, 1,000 kg of Depleted Uranium, 1,000 kg of Thorium, and 50 effective grams of special fissionable materials do not require an export license and is therefore not subject to NCA. In the US, the quantitative threshold for requiring an export license is different from that of ROK. For example, special fissionable materials that are not Pu are required if the individual shipment exceed 1 effective gram or 100 effective grams per year. The difference in the quantitative thresholds for NM between the two countries mean that the same item may be subject to NCA under US standards, but not under ROK’s. For example, the export of 8 grams of highly enriched uranium (93%) contained in a neutron detector would not be subject to the NCA in ROK, but would be considered NM subject to a NCA and required a special license in the US. Of course, in order to ensure the application of safeguards and physical protection to all NM transferred between the two countries, the agreement may not include a quantitative threshold for NM. However, the absence of such a threshold can lead to different conclusions by the two countries on the same item and make it challenging to control retransfers. The definition of quantitative standards will be necessary in the supplementary administrative arrangement for the practical control and management of NM subject to the NCA.

이 글은 남한 동해안에 유입된 북한 생활쓰레기로부터 시작된다. 그동안 북한 쓰레기가 남한에 유입된다는 사실은 해양쓰레기 실태조사 관련 연구 에서 주로 이루어졌다. 환동해권 해양쓰레기 유입 등에 관한 연구에서도 주로 한국과 일본, 극동러시아 등의 유입 현황에 관한 연구는 있지만, 북 한은 논의의 대상에서 제외되었다. 본 연구는 기존의 해양학 관점이 아닌 북한학 관점에서 남한 해안에 유입된 북한 쓰레기 문제를 다루었다. 북한 생활쓰레기 중 상품포장지는 직접적으로 북한 상품 생산 현황과 브랜드 등을 알 수 있으며, 간접적으로는 북한 내 경제 상황과 상품 유통 지역망 등을 알 수 있기 때문이다. 동해안 지역에서 수거한 북한제품 포장지를 살 펴보면 대부분 생산공장은 평양으로 표기되었다. 이를 통해 평양에서 생산 한 제품이 동해안 지역으로 유통됨을 알 수 있다. 또한 동해안 지역은 북 한을 대표하는 대도시인 원산, 청진, 함흥, 라선 등이 있는데, 실제로 상품 포장지에는 이 지역 생산공장이 표기되는 사례도 있었다. 김정은 집권 이 후 매년 국가적 차원에서 국가디자인전시회를 개최할 만큼 산업미술을 강 조하는데, 특히 상품의 고유한 특징을 표현하는 상표도안을 강조한다. 본 연구에서는 동해안 주요 도시에서 생산한 제품을 중심으로 같은 품목이지 만 공장별로 어떻게 상표도안이 다른지 살펴봤다. 북한 쓰레기에 대한 북 한학적 시각과 해양학적 시각의 학제간 연구를 통해 남한에 유입되는 북 한 생활쓰레기에 대한 연구의 폭을 넓혀갈 필요가 있다.

This paper reports the results of an experimental examination using X-rays to test annealing materials for lapped bearing steel (STB2), to confirm the validity of the weighted averaging analysis method. The distribution behavior for the sin diagram and the presence or absence of differences in the peak method, half-value breadth method, and centroid method were investigated. When lapping the annealed bearing steel (STB2) material, a residual stress state with a non-directional steep gradient appeared in the surface layer, and it was found that the weighted averaging analysis method was effective. If there is a steep stress gradient, the sin diagram is curved and the diffraction intensity distribution curve becomes asymmetric, resulting in a difference between the peak method, half-value breadth method, and centroid method. This phenomenon was evident when the stress gradient was more than 2~3 kg/mm2/μm. In this case, if the position of the diffraction line is determined using the centroid method and the weighted averaging analysis method is applied, the stress value on the surface and the stress gradient under the surface can be obtained more accurately. When the stress gradient becomes a problem, since the curvature of the sin diagram appears clearly in the region of sin > 0.5, it is necessary to increase the inclination angle  as much as possible. In the case of a lapping layer, a more accurate value can be obtained by considering  in the weighted averaging analysis method. In an isotropic biaxial residual stress state, the presence or absence of  can be determined as the presence or absence of strain for sin≈0.4.

The surge in food delivery systems during the coronavirus 2019 pandemic necessitated this study of heavy metal migration from food contact materials (FCMs). A total of 104 samples of FCMs, comprising 51 polypropylene (PP), 21 polyethylene (PE), and 32 polystyrene (PS) samples of six different types of FCMs (containers, covers, table utensils, cups, pouches, and wrappers) used for food delivery distributed in Korea, were collected and investigated for migration of three heavy metals (Pb, Cd, and As) using inductively coupled plasma–mass spectrometry (ICP-MS) to determine whether they complied with Korea’s Standards and Specifications for Utensils, Containers, and Packages. Acetic acid (4%, v/v) was used as the food simulant, and tests were performed at 100oC (in harsh conditions) for 30 min. Linearity of Pb, Cd, and As showed acceptable results with a coefficient of determination (R2) value of 0.9999. Limit of detection (LOD) and limit of quantification (LOQ) of Pb, Cd, and As were 0.001, 0.001, and 0.001 μg/L and 0.002, 0.003, and 0.003 μg/L, respectively. Accuracy and precision results complied with the criteria presented in the European Commission Joint Research Centre guidelines. The average concentration of Pb, Cd, and As migration detected in a total of 104 samples was 0.009–0.260 μg/L, which was very low compared with the migration specification set in the Standards and Specifications for Utensils, Containers, and Packages. The maximum level of Pb corresponded to 0.23% of the migration limit. There were no samples exceeding the limit. Thus, this study confirmed that the heavy metal contents of FCMs used for delivery food distributed in Korea were safely managed. The data from this study represent an invaluable source for science-based safety management of hazardous heavy metals migrating from FCMs used in the food delivery industry.

Metal material production process machinery is becoming larger due to the development of industry. Since there are many overseas manufacturers of large machines used in industrial fields, there are limitations in investigating the manufacturer's noise prediction method and measurement method. A noise map was prepared to obtain information necessary for noise reduction and to effectively manage noise companies. It was modeled with the drawings provided to prepare the noise map and the results of the actual measurement of the site. In order to improve the noise environment of workers, there was a noise reduction effect when a soundproof wall was installed between the noise source and the worker's workplace.

이 논문은 정적 재하상태에 있는 무피복 강합성보와 내화피복을 적용한 강합성보를 대상으로 화재 시 내부 온도 및 수직처짐에 대 한 내화피복의 영향을 평가한 결과를 제시한다. 열응력해석을 위한 화재하중으로는 American Society for Testing and Materials E119 의 표준화재곡선을 사용했으며, 강재거더 표면에 부착하는 내화재료의 방화효과를 구현하기 위해 외기에서 강합성보로 전달되는 열 의 전달계수를 감소시켰다. 실규모 무피복 강합성보에 대한 구조화재실험에서 내부 온도분포와 수직처짐을 측정하였고 실험 결과와 의 비교를 통해 비선형 구조화재해석 결과의 타당성을 검증하였다. 내화피복이 적용된 강합성보의 구조화재해석 결과로부터 강재거 더 표면에 내화재를 적용할 경우 동일 화재 조건에서 무피복 강합성보에 비해 내부 온도와 수직처짐이 감소함을 알 수 있었다. 또한 열 전달계수의 변화에 따른 열응력 응답으로부터 화재 시 강합성보의 온도 및 구조거동에 대한 내화피복의 영향을 제시하였다.