This study investigated the noise reduction effect according to the structure of the sound-absorption and insulating materials in order to maximize the noise reduction effect in various noise environments. For this purpose, the transmission loss according to the change in hole size of the performated plate in sound-absorption and insulating board was predicted using an CAE model. The sound-absorption and insulating board was modeled and the computation of the transmission loss was performed after applying the physical properties and boundary conditions. The pure sounds of 32Hz to 4,000Hz were generated, and the analysis was performed by changing the diameter and pitch of the perforated plate. It was confirmed that the influence of the diameter and pitch of the perforated plate is closely related to the structure that make up the sound-absorption and insulating material. In order to effectively reduce the variously changing noises, it is believed that a method of improving transmission loss for each frequency band of interest is needed by changing the structure of the sound-absorption and insulating material so that the diameter and pitch of the perforated plate can be changed.

The theoretical capacity of silicon-based anode materials is more than 10 times higher than the capacity of graphite, so silicon can be used as an alternative to graphite anode materials. However, silicon has a much higher contraction and expansion rate due to lithiation of the anode material during the charge and discharge processes, compared to graphite anode materials, resulting in the pulverization of silicon particles during repeated charge and discharge. To compensate for the above issues, there is a growing interest in SiOx materials with a silica or carbon coating to minimize the expansion of the silicon. In this study, spherical silica (SiO2) was synthesized using TEOS as a starting material for the fabrication of such SiOx through heating in a reduction atmosphere. SiOx powder was produced by adding PVA as a carbon source and inducing the reduction of silica by the carbothermal reduction method. The ratio of TEOS to distilled water, the stirring time, and the amount of PVA added were adjusted to induce size and morphology, resulting in uniform nanosized spherical silica particles. For the reduction of the spherical monodisperse silica particles, a nitrogen gas atmosphere mixed with 5 % hydrogen was applied, and oxygen atoms in the silica were selectively removed by the carbothermal reduction method. The produced SiOx powder was characterized by FE-SEM to examine the morphology and size changes of the particles, and XPS and FT-IR were used to examine the x value (O/Si ratio) of the synthesized SiOx.

The insecticidal activities of 27 different commercial products with environmentally friendly organic material (EFOM) against Scotinophara lurida, a major rice pest, were evaluated in the laboratory using spraying methods on plants and insects. Seven plant-derived organic farming materials (EFOM-8, -10, -12, -13, -19, -20, and -26) with high insecticidal effects when sprayed directly on the insect’s body rather than on the plant were selected. In the indoor rice pot test, all 7 EFOMs showed an insecticidal rate of over 73.3% under irrigated conditions. Notably, EFOM-13 and EFOM-20 demonstrated much higher insecticidal rates, ranging from 1.5 to 1.8 times, in irrigated conditions compared to drained conditions. In the semi-paddy field test, EFOM-10 (80% garlic extract), EFOM- 13 (62% neem extract), and EFOM-26 (70% sophora extract+28% ethyl alcohol+2% pyrethrum extract) exhibited a higher control value of 88.9% in the irrigated paddy on the 7th day, surpassing the control values in the drained paddy by 1.4 to 1.9 times. The control value in the irrigated rice paddy field sprayed with EFOM-10 reached 86.2% on the 7th day, which was 1.4 times higher than 61.9% in the drained paddy. Taken together, the findings suggest that direct contact of the insect’s body with sufficient amounts of spray solution and the maintenance of paddy irrigation can enhance the controlling effect of EFOMs. These findings will be valuable in developing an optimal S. luridacontrol strategy for application in rice paddy fields in the near future.

현대사회에서 미술교육과 미술작품 제작 현장은 정보와 이미 지를 비롯한 폭발적인 성장 속에서 새롭게 전개되고 있다. 이 러한 사회·문화적 방향성의 모색이 필요하고 새로운 관점의 재정립이 요구되는 상황에서 인간과 교육을 둘러싼 사회에서의 미술교육에 대한 새로운 방법론적 접근이 필요하다. 현재 우리 나라 미술교육현장에서 수채화는 점점 도태되어 간다. 화랑가 의 유화 선호, 재료와 도구 사용에 대한 인식, 기법의 난이도 등으로 인해 다른 장르의 그림보다 소외되고 있다. 그 이유 중 가장 큰 문제점은 기초과정을 넘어선 작품 만들기 과정에서 드 러나는데 그것이 바로 보조재료 사용에 대한 미숙함이다. 수채화 제작은 기름을 사용하는 유화와는 달리 물을 사용함으 로 예술의 표현형식과 감상 효과에서 동양인의 체취에 더 친근 감을 주는 매체이다. 수채화 물감을 이용한 작업은 그 자체로 하나의 도전이라고 할 수 있을 정도로 어렵지만, 보조재료를 이 용한 기법을 활용한다면 더 수준 높은 작품성을 발휘할 수 있을 것이다. 수채화에서 중요한 점은 수채화 물감이 투명체 매체라 는 것인데 미세한 입자로 이루어져 있어 어두운색 위에 밝은색 을 덧칠할 수 없다는 것 때문에 작품제작 시 상당한 난관에 부 딪혀 쉽게 작업을 포기하게 되는 것이 현실이다. 본 연구에서는 그런 점을 개선하기 위해 현대미술에서 수채 화 채색작업을 중심으로 <마스킹 액(Masking fluid)> 보조재 료의 활용방안을 제시하고자 한다. 마스킹액을 이용한 여러 가 지 수채화 채색방법과 보조재료의 활용법을 제안함으로써 현장 에서 갖는 문제점에 대해 논의하고, 더욱 질 높은 미술교육과 작품제작에 이바지할 방안을 새롭게 모색하고자 한다.

Asphalt concrete, which is used as a road base material, accounts for >90% of a road pavement. A huge amount of waste concrete and waste asphalt concrete aggregates are generated. Recently, carbon neutrality is promoted across all industries for sustainability. Therefore, to achieve carbon neutrality in the asphalt concrete industry, waste asphalt concrete aggregates should be recycled. Additionally, road base materials are prepared using additives to ensure structural stability, durability, and economic efficiency. In this study, recycled asphalt concrete aggregates were used to evaluate the physical properties of road base materials according to the type of polymer additive and mixing method, and the applicability of road base each material was evaluated. Results showed that when the acrylate-based polymer additive was mixed, the uniaxial compressive strength was 30% higher. Furthermore, the compressive strength of the split mix was improved by ~29% compared to the total mix.

PURPOSES : The purpose of this study is to conduct basic research on the development of repair materials for cross-sectional repair of the concrete of the lower slab ceiling of an old bridge. METHODS : To estimate the performance as restoration materials, cross section rebound test, compressive strength test, flexural strength test, and firing shrinkage test was done. Rebound test was done by weight of amount of rebound and weight of concrete accumulated in frame. Cross section rebound test was done by put ruler in the deepest part of concrete stick on frame. Compressive and flexural strength test was done based on KS F 2405 and KS F 2408. Firing shrinkage test was done based on ASTM C 1579-16. RESULTS : As a result of the experiment, an appropriate bonding thickness was secured by mixing natural fibers, polymers, early steel cement, and expansion materials, and the dust reducing agent was excluded due to the problem of lowering compressive strength. In addition, the amount of rebound was reduced by using a hydro mix nozzle, and plastic shrinkage cracks were also reduced due to the internal curing effect of natural fibers. CONCLUSIONS : This study was a basic study in the development of repair materials for cross-sectional repair of the lower ceiling of an aged bridge slab, and developed a material with appropriate performance. However, there is a problem that the amount of rebound and dust increases depending on the type of cement, so experiments will be conducted by changing the type of cement in future research.

The asphalt concrete industry, accounting for >90% of road pavement, is a crucial contributor to construction waste. This study focuses on the recycling of asphalt concrete recycled aggregates, which currently exhibits a low rate. We investigated the application of these aggregates, combined with hardener and mixing water, in the development of ecofriendly road base materials using circular aggregates. Results revealed that the 13-mm asphalt concrete recycled aggregates met all quality standards. However, the 25-mm aggregates did not conform to the reclaimed asphalt content standard; however, they met other quality standards. Moreover, the experimental results for the hardener and mixing water indicated compliance with all quality standards.

PURPOSES : Experimental findings pertaining to the mechanical properties and microstructures of calcium sulfo-aluminate (CSA) cement and amorphous calcium aluminate (ACA) cement based-repair mortars incorporated with anhydrite gypsum (AG) are described herein. METHODS : To prepare the mortars, the CSA or ACA as binders were adopted and the ratio of water–binder was fixed at 0.57. For comparison, mortar made of Type I ordinary Portland cement (OPC) was prepared. The fluidity, setting time, compressive and bond strengths and absorption of the mortars were measured at predetermined periods. In addition, the microstructures of paste samples using OPC, CSA or ACA were visually examined through SEM observation. RESULTS : The ACA-based mortars showed the increases in the fluidity, and the acceleration of the setting time. Furthermore, the ACAbased binder effectively enhanced the compressive and bond strengths of the mortars owing to amount of formation of C2AH8 hydrates. Meanwhile, the mortar with ACA showed an excellence absorption. CONCLUSIONS : Comparing with those of CSA-based mortars, the mechanical properties of ACA based-mortars were more remarkable. However, further studies regarding the durability of repair mortars using aluminate-based binders must be conducted to obtain the optimal mixture.

본 연구의 목적은 재료분야 국내 공동특허의 공동 출원인 정보를 이용하여 연구협력 네트워크의 구조, 특징, 진화를 탐구하는 것이다. 이를 위해 재료 기술분야(금속, 세라믹, 고분자 등 6개 기술분야) 및 혁신주체(산업계, 학계, 연구계)의 네트워크 구조 및 동태를 정량적으로 분석하며, 2010년∼2021년까지 한국의 공동특허 데이터를 활용하여 소셜 네트워크 분석(SNA)을 사용한다. 분석결과, 재료분야는 세부기술별로 네트워크의 차별점이 존재하며, 산업계, 학계, 연구계 등 혁신주체별 협력 강도의 명백한 단계별 특성을 가진다. 연구협력 네트워크의 규모는 점차 확장되어 ‘작은 세계’ 구조를 보여주고 있다. 본 연구를 통해 재료 정책 관점에서 지금까지 시행된 재료분야 산학연 협력 정책의 효과를 파악하는데 정책적 시사점을 제공함과 동시에, 보다 효과적인 재료 혁신주체 간의 네트워크를 구축하기 위한 근거 기반의 정책 수립에 도움이 될 수 있다.

In this study, we introduce the validation of the analysis guidelines through preliminary experiments of the draft analysis guidelines before analyzing waste materials (non-combustible). This validation data was applied the accuracy and efficiency of the separation and analysis for the waste such as steel generated from NPP. Steel (non-flammable) was leached the mixed acid and the leaching solution was separated by using the separation guidelines. Steel was corroded with radioactive RM (Co-60, Cs-137) and mixed acid. After drying, the corroded steel was measured the initial radioactivity by a HPGe detector (10,000 seconds). The sample was inserted in a beaker and leached with mixed acid (10 M HNO3 + 4 M HCl) for 2 hours. In this solution, it added 2 ml of H2O2 to increase the leaching effect. The ultrasonic device was adjusted so that the temperature does not exceed 60°C. After elution, the surface of the sample was washed with pure water. The weight of the sample was measured accurately, and recorded the weight loss rate after infiltration. The leaching sample was measured radioactivity by a HPGe detector (10,000 seconds). It was calculated the recovery rate based on the difference in total radioactivity before and after leaching. Before the test, radioactive RM (Co-60, Cs-137) was radioactive deposited by corrosion, but Cs- 137 was not detected in the initial gamma measurement and only Co-60 nuclides were deposited. The recovery rate test results were confirmed to be about 100%.