PURPOSES : Sprinkler facilities play a crucial role in extinguishing fires in the early stages of a building blaze. Data indicate that more than 96% of fires are suppressed by sprinklers before growing out of control. However, corrosion and pitting of the sprinkler piping can reduce system performance as facilities age. The purpose of this study is to develop an eco-friendly water-soluble corrosion inhibitor to improve the reliability and longevity of sprinkler piping. METHODS : This study compared and analyzed silicate-based sprinkler piping shrinkage agents as corrosion inhibitor against existing commercial options. Tests were conducted to evaluate reactivity with fire extinguishing water, including electrolyzed reduced water and normal water. The anticorrosive performance of the silicate-based corrosion inhibitor was evaluated under various conditions to establish suitability before potential development or commercialization. RESULTS : The new corrosion inhibitor demonstrated eco-friendly performance. In testing, none of the primary four hazardous substances that pose the most risk of harm to the human body (specifically, arsenic (As), lead (Pb), cadmium (Cd), and mercury (Hg)) were detected. The inhibitor effectively reduced corrosion of carbon steel (SPP), with weight loss rates averaging 0.12% and not exceeding 0.27%. For copper (CDA 110) weight loss rates were up to 0.03%. Testing under constant temperature and humidity conditions show that the inhibitor kept weight loss was below 0.002 g, with no significant numerical value for the weight loss rate. Overall, the results indicate the potential for an environmentally-safe corrosion inhibitor. CONCLUSIONS : The optimal silicate-based sprinkler system can provide real-time sensor information such as oxygen saturation, pH concentration, and total dissolved solids (TDS). These metrics are closely related to the aging process. By linking this system with an aging monitoring solution, maintenance costs and safety could be improved over the lifespan of the sprinkler system. The sensors and monitoring capabilities are expected to enhance maintenance efficiency and equipment reliability.

PURPOSES : This study aims to propose drone-command standard operating procedure (SOP) guidelines and Analyze their potential application to increase the use and utility of drones in urban disaster situations. Although the effectiveness and efficiency of obtaining disaster-situation information through drones have been verified by previous studies and practical experience, a survey of actual drone usability indicated a utilization rate of only approximately 4.13%. METHODS : To provide guidance for improving drone command SOPs, prior research and relevant literature were reviewed to identify commonalities between disaster-response command and control and drone use. A sample of 73 active-duty firefighters, including incident commanders (ICs) and drone pilots, were surveyed and interviewed. The data were analyzed and categorized to establish the reasons why drones are not actively used in urban disaster-response procedures. RESULTS : The primary reasons identified for not actively utilizing drones in urban disaster areas were the lack of a drone command and control system and the lack of clear criteria for when to use drones in disaster situations. In addition, many problems were found in drone-operation procedures, including emergency flight approval, securing takeoff and landing sites, and accident burden due to urban flight obstacles. To address the issues identified, standards were proposed for the type, size, and scope of urban disasters requiring drone response; for accident-prevention on basic missions and through flight safety procedures; and for installing a video transmission and reception system to easily share drone video information with ICs. CONCLUSIONS : Application of the drone-command SOP guidelines to actual urban disaster situations by disaster type will help to improve the efficiency of information acquisition and flight safety. This is expected to enable increased drone utilization. In future, extension of the research reported in this paper beyond the Seoul metropolitan area via additional follow-up studies has the potential to establish applicability of the proposed SOP guidelines to a wide variety of environments and organizational characteristics.

본 연구는 코이어 배지를 이용한 오이 수경재배에서 배지 포 수액의 종류와 정식 방법에 따른 생육 및 생산성을 검증하여 가장 효율성이 높은 재배 방법의 선발을 위하여 수행되었다. 포수액은 배양액(S)과 원수(W), 육묘는 암면큐브 육묘(RC), 암면 플러그묘(RP), 슬라브 직파(DS)로 하였다. 재배 기간을 동일하게 하기 위하여 기준일은 파종일로 하였다. 초기 생육 량은 S 처리에 서 유의하게 높았으나, 생육기간이 길어질수록 처리 간 차이가 감소하였다. 정식 방법과 생육량 간에는 관계 성이 나타나지 않았으나, 포수 방법에 따라 동일한 정식방법 간에도 다른 결과가 나타났다. 생산성도 동일한 경향으로 초 기 수확기인 파종 후 6－8주까지는 S 처리에서 수확과의 수가 유의하게 많았으며, 이후 동일한 기간 수량의 격차가 해소되 었다. 누적 수량은 초기 수확량의 차이로 인하여 S 처리에서 유의하게 높았다. 식물체의 생육과 과실 생산성은 유사한 경 향으로 선형적인 관계성을 나타내었다. 정식 방법 간에는 상 관성을 나타내지 않았으나, S의 DS 처리가 초기 근권부 안정 적인 양·수분 공급으로 초기 생육 및 수량이 가장 많은 경향이 었다. 따라서 S 처리한 배지에 DS 방식이 식물체의 생육 및 생 산성에 가장 유리할 뿐만 아니라 재배단계 간소화를 통한 노 동력 및 생산 원가 절감으로 경제성 측면에서도 기여할 수 있 을 것으로 생각된다.

본 연구에서는 해양공간 통합관리 수단의 지원책으로 활용되는 해양공간 정책 시뮬레이터 기술에 대한 한국, 중국, 일본, 미국, 유럽 등 주요 5개국에 대한 정량분석을 위한 유효특허 1,474건을 도출하고, 연도별, 국가별 특허출원 동향 및 워드 클라우드 분석을 통해 국내 기술 경쟁력 및 국내·외 기술 트렌드를 파악하였다. 분석 결과 해양공간 정책 시뮬레이터 기술의 경우 중국(1,254건, 85.1%) 주도의 특허출원이 활발하게 이루어지고 있으며, 세부 기술별로는 어업환경 변화예측 및 활용 시뮬레이터(AC)가 392건(26.6%)으로 가장 높은 것 으로 나타난다. 핵심 키워드 변화를 통해 최근에는 다중 데이터의 수집과 데이터의 탐지, 예측, 평가 등으로 기술 트렌드가 이루어지고 있 음을 확인하였으며, 중국 주도의 시장 독과점 및 선점에 대비하기 위해 주변 기술에 대한 특허출원 고려 및 표준화 선점 등의 연계 전략 을 통한 대비와 정부 차원의 해양공간 정책 시뮬레이터 기술 연구개발에 대한 적극적인 정책적 지원이 필요함을 진단하였다.

Composite-based piezoelectric devices are extensively studied to develop sustainable power supply and selfpowered devices owing to their excellent mechanical durability and output performance. In this study, we design a leadfree piezoelectric nanocomposite utilizing (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCTZ) nanomaterials for realizing highly flexible energy harvesters. To improve the output performance of the devices, we incorporate porous BCTZ nanowires (NWs) into the nanoparticle (NP)-based piezoelectric nanocomposite. BCTZ NPs and NWs are synthesized through the solidstate reaction and sol-gel-based electrospinning, respectively; subsequently, they are dispersed inside a polyimide matrix. The output performance of the energy harvesters is measured using an optimized measurement system during repetitive mechanical deformation by varying the composition of the NPs and NWs. A nanocomposite-based energy harvester with 4:1 weight ratio generates the maximum open-circuit voltage and short-circuit current of 0.83 V and 0.28 A, respectively. In this study, self-powered devices are constructed with enhanced output performance by using piezoelectric energy harvesting for application in flexible and wearable devices.

본 연구는 딸기의 삽목 육묘 시 묘소질을 향상시키고 품질을 증진시키기 위한 지베렐린 효과를 검증하기 위해 수행되었다. 품종은 ‘설향’을 대상으로 하였고, 삽목 시 삽수의 기부를 30, 60분간 GA3 50, 100, 150mg·L-1에 침지 처리하고 증류수 침 지를 대조구로 두었다. 정식 시 묘소질 조사 결과 엽수와 SPAD 값은 지베렐린 침지시간이 길수록 증가하였고, 초장, 엽병장, 엽장, 엽폭, 엽면적은 침지시간과 농도 간의 상호작용에 따라 유의하게 값이 변하였다. 관부직경은 같은 농도라 할지라도 침지시간에 따른 차이가 나타났으며 30분, 100mg·L-1 처리를 제외하고 모두 직경이 8.0mm 이상으로 우량한 묘가 생성되 었으며, T/R률은 30분, 50mg·L-1 처리에서 유의하게 작아 식 물체 활력이 가장 우수했다. 양자수율은 농도가 150mg·L-1일 때 저조하였고, 지베렐린 처리 농도가 높을수록 양자수율이 감소하는 경향을 나타냈다. NPQ는 대조구 대비 30분, 150mg·L-1 처리에서 유의하게 작아 묘 스트레스 감소에 효과 가 있었다. 항산화물 함량은 30분, 50mg·L-1 처리와 60분, 150mg·L-1 처리에서 높게 나타났고, 정식 후 생육조사 결과 화아분화 정도에 미치는 지베렐린의 부정적 영향은 없었다. 따라서, ‘설향’ 딸기의 삽목 육묘 시 지베렐린 처리는 정식묘 양성에 효과가 있는 것을 확인할 수 있었으며, 이때 대조구 대 비 생육 증진 및 품질 향상을 위해서는 삽수 기부를 50mg·L-1 의 지베렐린에 30분 침지처리하는 것이 보다 적정한 것으로 판단되었다.

본 연구는 기존 (불)투과형 사방댐의 부식 및 시공성 등의 문제를 보완하고자 GFRP와 CFRP를 사용하여 내부식성 투과형 사방댐을 설계한 선행연구의 후속 연구로써 FRP로 제작된 격자형 사방 구조물(Grid)을 설계하여 탈부착이 가능한 투과 형 사방댐을 개발하기 위한 기초 연구이다. 이를 위해 탄소산업진흥원(K-Carbon)의 상용 Grid 제원을 인용하였으며, Grid를 구성 하는 띠(Strip)는 41×21개로 총 4000×2000×1.5 mm의 크기로 설계하였다. Grid의 개발을 위한 기초 연구라는 특성상 Grid의 지지 부(Slot)와 충진재는 파괴되지 않는다고 가정하였으며, FRP의 파괴 이론인 Hashin Damage Criteria에 따라 Grid의 설계하중 작용 시의 안전성을 상용 유한요소해석 프로그램인 ABAQUS로 평가하였다. 그 결과, 0.01~0.03sec 내에서 GFRP와 CFRP Grid가 파괴 되었으며, 이는 Grid의 성능이 충분하지 못함을 의미한다. 이에 따라 Grid의 성능 향상을 위해서 GFRP 및 CFRP(면재)와 Balsa Wood(심재)로 구성된 Sandwich Grid를 개발하였으며, 동일 조건에서 해석을 수행한 결과, Grid 대비 Sandwich Grid가 약 126~140 배 뛰어난 성능을 보였다. 결론적으로 Sandwich Grid를 이용한 탈착형 사방댐은 내구성 및 경제성 측면에서 이점이 분명하다 판 단되지만, 이는 일부 가정 사항과 수치 해석을 기반으로 하는 결과이므로 향후 추가 연구가 수행되어야 할 필요가 있다.

To produce super sweet corn sikhye, substituted for sweetener, the ratio of rice and super sweet corn was adjusted and processed with complex enzymes during saccharification, and their physicochemical and sensory properties were analyzed. The soluble solid content of the control and Corn-5 showed significantly high content at 13.50 °Brix, and the reducing sugar content of Corn-5 showed the highest content at 9.45%. The control showed the lowest free sugar content among all the experimental groups, excluding maltose content. In the enzyme-treated corn sikhye group, as the amount of super sweet corn increased, the content of sucrose decreased and the contents of glucose and fructose increased. The content of ascorbic acid and polyphenol compounds increased as the amount of super sweet corn increased. DPPH and ABTS radical scavenging abilities increased with increasing ratio of super sweet corn and enzyme treatment compared to the control. In the case of sensory evaluation, Corn-3, which substituted 30% of super sweet corn for rice and treated with enzymes, showed higher evaluations in taste, sweetness, and overall preference than those of the control.

본 연구에서는 수소 자원의 활용도가 높아짐에 따라 수소 저장 용기의 내진 성능을 평가하기 위해 수소 저장 시설을 방문하여 현장 조사를 수행하였다. 외관 조사 중, 수조 저장 용기의 지지부에서 부식이 진행됨을 확인하였고, 이에 대한 대책안 으로 내부식성 재료인 CFRP로 대체하여 성능을 평가, 검증하였다. 이를 위해 현장 조사 결과를 바탕으로 상용 유한요소해석 프 로그램인 ABAQUS를 사용하였으며, 해석 결과 CFRP로 제작된 수소 저장 용기의 지지부는 강재 대비 약 12배 이상 뛰어난 성 능을 보였다. Hashin Damage Criteria를 기반으로 CFRP 지지부의 안전성 검토를 수행한 결과 최대 손상 지수가 0.065로 확인되 었다. 기초부 콘크리트의 경우, 쪼갬 및 휨 인장 응력에 대한 안전성을 검토하였으며, 허용 강도 대비 7~36%의 안전도를 보였 다. 이를 근거로 CFRP를 수소 저장 용기의 지지부에 적용하는 것은 합리적이며, 뛰어난 경제성을 보인다. 다만, 이러한 결과는 수치 해석에 의하므로 실규모 지진동 모사 시험을 통해 해석 모델의 신뢰성을 보충할 필요가 있다.

세계 각국은 온실가스 배출을 줄이기 위하여 활발한 노력을 하고 있다. 한국도 노후화된 석탄발전을 폐지하고 LNG 발전으로 전환하는 정책을 추진하고 있다. 그러나, 한국은 가스터빈 제작 기술이 국산화되지 않아서 해외 제작사로부터 전량 수입하여 설치하고 있다. 따라서, 본 논고에서는 가스터빈 발전산업에 대한 국내·외 환경을 살펴보고, 이를 기반으로 PEST-SWOT-AHP 방법론을 적용하여 한국형 가스터빈 기술개발 및 보급 확대 추진전략을 제안하였다. 연구결과, 한국형 가스터빈 기술개발과 보급 확대 전략은 1) 가스터빈 기술개발 및 사업화 촉진을 위한 발전공기업의 역할 강화, 2) 온실가스 감축을 위한 LNG 발전 비중 확대, 3) 정부의 적극적인 가스터빈 산업 생태계 조성 노력, 4) LNG 발전소 건설에 대한 국민 공감대 형성 등으로 요약할 수 있다.

화장품 소재는 안전성이 무엇보다 중요시된다. 화장품에 사용되는 기존의 보존제인 PE에 대장 균 효소 β–gal을 이용하여 안전성이 증가된 PE-gal을 생합성하였다. 화장품 소재로 사용하기 위해 생합 성된 생성물인 PE-gal의 피부 흡수도를 기존의 보존제인 PE와 비교하기 위해 Franz Diffusion cell Assay 시스템을 이용하여 경피투과도를 측정하였다. 같은 질량농도의 시료를 사용하였을 때 PE의 Flux 값, Kp 값은 시간이 지날수록 증가하는 것으로 나타났으나 PE-gal은 투과도를 측정할 수 있을 만큼 투과되지 못 하였다. 이는 PE의 피부투과도가 생합성된 PE-gal 배당체보다 높다는 것을 나타낸다. Marzulli 등에 따라 Kp 값을 이용하여 투과 정도를 확인하였을 때 PE의 투과속도는 1mg/mL의 농도에서 느림(slow)으로 측정 되었다. 따라서 배당체 형태의 PE-gal은 PE에 비해 경피 투과도가 현저히 낮게 나타났다.

High-Manganese (Mn) austenitic steel, with over 24 wt% Mn content, offers outstanding mechanical properties in cryogenic settings, making it a potential replacement for existing cryogenic materials. This high manganese steel exhibits high strength, ductility, and wear resistance, making it promising for applications like LNG tanks, flanges, and valves. To operate in cryogenic environments, hot forging and heat treatment processes are vital, especially in flange production. The cooling rate during high-temperature cooling after hot forging plays a critical role in influencing the microstructure and mechanical properties of high manganese steel. The rate at which cooling occurs during this process influences the size of the grains and the distribution of manganese and consequently has an impact on mechanical properties. This study assessed the microstructure and mechanical properties based on different cooling rates during the hot forging of High-Mn steel flanges. Comparing air and water cooling after hot forging, followed by heat treatment, revealed notable differences in grain size. These differences directly impacted mechanical properties such as tensile strength, hardness, and Charpy impact property. Understanding these effects is crucial for optimizing the performance and reliability of High-Mn steel in cryogenic applications.

Al2O3 has excellent sintering properties and is important in semiconductor manufacturing processes that require high-temperature resistance and chemical inertness in a plasma environment. In this study, a comprehensive analysis of the chemical characteristics, physical properties, crystal structure, and dispersion stability of three commercially available Al2O3 powders was conducted. The aim was to provide a technological foundation for selecting and utilizing appropriate Al2O3 powders in practical applications. All powders exhibited α-Al2O3 as the main phase, with the presence of beta-phase Na2O-11Al2O3 as the secondary phase. The highest Na+ ion leaching was observed in the aqueous slurry state due to the presence of the secondary phase. Although the average particle size difference among the three powders was not significant, distinct differences in particle size distribution were observed. ALG-1SH showed a broad particle size distribution, P162 exhibited a bimodal distribution, and AES-11 displayed a uniform unimodal distribution. Highconcentration Al2O3 slurries showed differences in viscosity due to ion release when no dispersant was added, affecting the electrical double-layer thickness. Polycarboxylate was found to effectively enhance the dispersion stability of all three powders. In the dispersion stability analysis, ALG-1SH exhibited the slowest sedimentation tendency, as evidenced by the low TSI value, while P162 showed faster precipitation, influenced by the particle size distribution.

By developing a high-quality plexiglass sign using LED, it is possible to respond to international competitiveness and effectively cope with market expansion measures. The degree of inhalation of the fine dust blown by the air nozzle was tested so that it was not blown into the air. As a result of this test, the acrylic absorption rate was 82%, an increase of 20% from 60% before improvement, and the working environment was improved. With the development of the dust extraction device for the acrylic processing machine in this study, the suction and removal of acrylic fragments or dust is smoothly performed, resulting in a cleaner, more hygienic and improved safety through the improvement of the working environment. As a result of comparing the amount of burr generated in the plexiglass material and comparing the degree of test performance for reaching 24,000 rpm, it reached 24,000rpm.

In alignment with South Korea's “3020 Renewable Energy Expansion Plan,” this study focuses on the developing large-scale floating wind turbines. It addresses the challenges of increased size and cost in floating structures for wind turbines over 10MW. This paper details the preliminary design of a novel floating substructure utilizing composite materials(ie, EVA). Structural analysis was performed using ABAQUS, accounting for both typical and extreme wind conditions. Results from the analysis validate that the substructure design is adequately feasible for implementation.

Since ships are exposed to noise and vibration for a long time in seas isolated from land, the stress of workers is high, requiring studies on the improvement of the problem. In addition, the health of crew members on fishing vessels, unlike commercial ships, carrying out fishing activities is closely related to fishing performance. However, considering that most of IMO's guidelines apply to merchant ships, provisions should be made for vibration in accommodation areas of fishing vessels. Accordingly, this study, applying the revised ISO 20283-5:2016 standard and through experiment, investigated the vibration characteristics of the accommodation area for each operating conditions of a 1000-ton trawler fishing vessel. Within the scope of the study and the full-ahead mode, the vibration was highest in the engine control room (4.17mm/s) while the acceptable standard was satisfied sufficiently in all conditions. Application of the merchant vessel vibration standard to fishing vessel is expected to improve the working environment of fishing vessel crew members.

본 연구는 희귀난치 질환 자녀를 둔 가족의 생활 실태와 지원 욕구를 파악하여 지원방안을 모색하는 데 목적이 있다. 이를 위해 2020년 기준 전국의 희귀난치 환아 가족 약 169천 명 중 할당표본추출(quota sampling) 을 통해 모집된 총 263명을 대상으로 설문조사를 하였다. 그 결과, 희귀 난치 환아 가족의 주양육자는 여성으로 자녀 돌봄 및 간병 비중이 높았 고, 치료비지출로 인한 경제적인 부담이 매우 높았다. 전체 삶의 질 평 균 및 삶의 질 하위요인 전반에서 보통 이하의 인식수준을 보였고, 교 육 현장이나 과정에서 자녀의 질병에 대한 인식과 대처 관련 어려움이 큼을 확인하였다. 희귀난치 질환 및 자녀의 재학 상태에 따른 인식수준 도 매우 낮은 수준이었다. 이런 실태에 근거하여 가족지원을 위한 다차 원적인 지원방안을 제언하였다.

This study conducted an investigation into the effects of fruit type and cultivation practices (organic and conventional) on soil characteristics and soil arthropod communities within apple, blueberry, grape, peach, and pear orchards. The collection of soil arthropod communities was achieved through the utilization of pitfall traps, with concurrent measurements taken for soil moisture content, electrical conductivity, and temperature. The findings of this study unveiled substantial impacts attributed to fruit type and cultivation practices on soil characteristics. Specifically, within organic apple orchards, discernibly higher levels of soil moisture content, electrical conductivity, and temperature were observed when compared to their conventional counterparts. The investigation into soil arthropod communities yielded a total of 1,527 individuals, classified in to five phyla and 15 orders. The range of abundance, species richness, and diversity indices varied across conventional and organic orchards. Cultivation practices were found not to exert a significant influence on soil arthropod community characteristics. However, Non-metric Multidimensional Scaling (NMDS) analysis indicated a significant differentiation in soil arthropod community structure based on cultivation practices. This study underscores the importance of considering vegetation structure and environmental characteristics that may influence soil arthropod communities comprehensively when assessing the impact of cultivation practices on soil arthropods. Furthermore, it emphasizes the need to account for both the characteristics and structure of soil arthropod communities in understanding the implications of cultivation practices on these organisms.

To improve usability of super sweet corn, extracts were prepared with hydrolytic enzyme and changes in physicochemical and antioxidant properties were analyzed. Soluble solids and reducing sugars contents were higher in all enzyme treatment groups than in the control. When enzyme treatment time increased, contents of soluble solids and reducing sugars were also increased. There was no significant difference in lightness between treatment groups, with redness showing the highest value in the control and yellowness showing the highest value in the invertase treatment group. Free sugar content in the control was the lowest. However free sugar content in the enzyme combination treatment group was increased by more than four times compared to that in the control. Contents of ascorbic acid, flavonoids and polyphenols were higher in the enzyme treatment group than in the control. In particular, the enzyme combination treatment group showed the highest content. DPPH and ABTS radical scavenging abilities were significantly higher in all enzyme treatment groups than in the control. Radical scavenging abilities of cellulase treatment group and enzyme combination treatment group showed high activity. The activity increased when enzyme treatment time increased. The combined enzyme treatment method for super sweet corn was suitable for food processing.

Many changes in the scale and structure of the Korean rice cropping system have been made over the past few decades. Still, insufficient research has been conducted on the sustainability of this system. This study analyzed changes in the Korean rice cropping system’s sustainability from a system ecology perspective using an emergy approach. For this purpose, an emergy table was created for the Korean rice cropping system in 2011, 2016, and 202, and an emergy-based indicator analysis was performed. The emergy analysis showed that the total emergy input to the rice cropping system decreased from 10,744E+18 sej year-1 to 8,342E+18 sej year-1 due to decreases in paddy field areas from 2011 to 2021, and the proportion of renewable resources decreased by 1.4%. The emergy input per area (ha) was found to have decreased from 13.13E+15 sej ha-1 year-1 in 2011 to 11.89E+15 sej ha-1 year-1 in 2021, and the leading cause was a decrease in nitrogen fertilizer usage and working hours. The amount of emergy used to grow 1 g of rice stayed the same between 2016 and 2021 (specific emergy: 13.3E+09 sej g-1), but the sustainability of the rice cropping system (emergy sustainability index, ESI) continued to decrease (2011: 0.107, 2016: 0.088, and 2021: 0.086). This study provides quantitative information on the emergy input structure and characteristics of Korean rice cropping systems. The results of this study can be used as a valuable reference in establishing measures to improve the ecological sustainability of the Korean rice cropping system.