A high-pressure in-situ permeation measuring system was developed to evaluate the hydrogen permeation properties of polymer sealing materials in hydrogen environments up to 100 MPa. This system employs the manometric method, utilizing a compact and portable manometer to measure the permeated hydrogen over time, following high-pressure hydrogen injection. By utilizing a self-developed permeation-diffusion analysis program, this system enables precise evaluation of permeation properties, including permeability, diffusivity and solubility. To apply the developed system to high-pressure hydrogen permeation tests, the hydrogen permeation properties of ethylene propylene diene monomer (EPDM) materials containing silica fillers, specifically designed for gas seal in high-pressure hydrogen environments, were evaluated. The permeation measurements were conducted under pressure conditions ranging from 5 MPa to 90 MPa. The results showed that as pressure increased, hydrogen permeability and diffusivity decreased, while solubility remained constant regardless of pressure. Finally, the reliability of this system was confirmed through uncertainty analysis of the permeation measurements, with all results falling within an uncertainty of 11.2 %.
Gas sensors play a crucial role in monitoring harmful gas concentrations and air quality in real-time, ensuring safety and protecting health in both environmental and industrial settings. Additionally, they are essential in various applications for energy efficiency and environmental protection. As the demand for hydrogen refueling stations and hydrogen fuel cell vehicles increases with the growth of the hydrogen economy, accurate gas concentration measurement technology is increasingly necessary given hydrogen's wide explosion range. To ensure safety and efficiency, gas sensors must accurately detect a wide range of gas concentrations in real-world environments. This study presents two types of gas sensors with high sensitivity, stability, low cost, fast response time, and compact design. These sensors, based on volume and pressure analysis principles, can measure gas filling amounts, solubility, diffusivity, and the leakage of hydrogen, helium, nitrogen, and argon gases in high-density polyethylene charged under high-pressure conditions. Performance evaluation shows that the two sensors have a stability of 0.2 %, a resolution of 0.12 wt・ppm, and can measure gas concentrations ranging from 0.1 wt・ppm to 1400 wt・ ppm within one second. Moreover, the sensitivity, resolution, and measurement range of the sensors are adjustable. Measurements obtained from these sensors of gas filling amounts and the diffusivity of four gases showed consistent results within uncertainty limits. This system, capable of real-time gas detection and characterization, is applicable to hydrogen infrastructure facilities and is expected to contribute to the establishment of a safe hydrogen society in the future.
Springtails (class Collembola) play a crucial role in soil ecosystems. They are commonly used as standard species in soil toxicity assessments. According to the ISO 11267 guidelines established by the International Organization for Standardization (ISO), Allonychiurus kimi uses adult survival and juvenile production as toxicity assessment endpoint. Conventional toxicity assessment methods require manually counting adults and larvae under a microscope after experiments, which is time-consuming and laborintensive. To overcome these limitations, this study developed a model using YOLOv8 to detect and count both adults and juveniles of A. kimi. An AI model was trained using a training dataset and evaluated using a validation dataset. Both training and validation datasets used for AI model were created by picturing plate images that included adults and larvae. Statistical comparison of validation dataset showed no significant difference between manual and automatic counts. Additionally, the model achieved high accuracies (Precision=1.0, Recall=0.95 for adults; Precision=0.95, Recall=0.83 for juveniles). This indicates that the model can successfully detect objects. Additionally, the system can automatically measure body areas of individuals, enabling more detailed assessments related to growth and development. Therefore, this study establishes that AI-based counting methods in toxicity assessments with offer high levels of accuracy and efficiency can effectively replace traditional manual counting methods. This method significantly enhances the efficiency of large-scale toxicity evaluations while reducing researcher workload.
Gas sensors are crucial devices in various fields including industrial safety, environmental monitoring, gas infrastructure and medical diagnosis. These sensors measure specific gases in different environments, guaranteeing operational safety and efficiency through precise on-site measurements. Designed for high sensitivity, stability and reliability, gas sensors must also be cost-effective, quickly responsive and compact. To address these diverse requirements, we have developed two types of gas sensors based on the volumetric and the manometric method. These sensors operate by measuring the gas volume and the pressure changes, respectively, of the emitted gas. These sensors are capable of determining gas transport parameters such as gas uptake, solubility and diffusion coefficient for gas-charged polymers in high pressure environment. The sensors provide rapid responses within one second and can measure gas concentrations ranging from 0.01 wt ppm to 1500 wt ppm with adjustable sensitivity and measurement ranges. Performance evaluations demonstrate the sensors' reliability, adaptability to varying measurement ranges and stability under temperature and pressure fluctuations. As a result, this sensor system facilitates the real time detection and analysis of gas transport properties in pure gases including H₂, He, N₂, O₂ and Ar, making it suitable for pure gas sensing.
This study investigates the opening force required for shucking farmed oysters to support the development of automated oyster-shucking systems. Oysters sourced from Yeosu and Tongyeong were tested for shell length, width, height, total weight, meat weight, and opening force. Results showed an average opening force of 8.1 kgf for one-year-old Yeosu oysters, 7.4 kgf for one-year-old Tongyeong oysters, and 8.7 kgf for two-year-old Tongyeong oysters, with correlations to shell width, height, and meat weight depending on production sea area and growing age. These findings highlight production sea area and growing age-based differences in oyster characteristics, contributing foundational data to advancing automation in oyster shucking.
This review examines the importance of measuring practical enteric methane emissions from ruminants, considering their significant impact on global warming. Global warming is significantly driven by an increase in greenhouse gases, with rising methane (CH4) emissions from ruminants accelerating global warming recently. To successfully mitigate CH4 emissions and establish effective strategies, it is essential to apply reliable measurement techniques. This will allow for an accurate assessment of on-farm CH4 emissions. The priority should be to gather CH4 emission data that reflects the actual state of CH4 emissions from ruminants. The review provides an overview of the methods used to measure CH4 emissions from ruminants by compiling existing researches. It introduces the concepts, principles, and limitations of these methods to facilitate comparisons between existing approaches. This review discusses methods for measuring enteric CH4 emissions from ruminants at the farm level, including the tracer technique, laser methane detector, GreenFeed, and sniffer system. These methods are highlighted as potential tools to accumulate substantial data on on-farm CH4 emission from domestic animals with provides examples of international cases. Among these, this review introduces the Sniffer method, a CH4 emission measurement techniques that are suitable for on-farm use under domestic conditions, and emphasizes the necessity of its application. In addition, by presenting international cases where predictive models were developed based on on-farm CH4 measurement techniques, it is projected that if predictive models for CH4 emissions are developed by accumulating data at the farm level, it can contribute to sustainable livestock industry in various promising ways.
목적: 본 연구의 목적은 고령자 대상 건강증진 그룹 중재 프로그램이 투입 비용 대비 산출하는 사회적 효용에 대해 분석하고자 한다. 연구방법: 원주시에서 수행된 지역사회 고령자 대상의 건강증진 그룹 중재연구 3개를 분석 대상으로 하였다. 사회투자수익률(Social Return on Investment: SROI) 분석은 선행연구의 가이드라인을 참고하여 수행하였다. 결과: 분석 결과 고령자 대상 그룹 중재 프로그램은 모두 투입된 비용 대비 높은 사회적 가치를 창출하였으며, 연구를 기획하고 중재를 제공한 참여 연구원에게도 비용 대비 높은 사회적 가치가 창출된 것으로 나타났다. 결론: 본 연구는 고령자 대상 건강증진 그룹 중재 프로그램의 개발과 평가에 SROI 방법론을 적용하여 효과적인 결과를 얻었다는 점에서 의의가 있다. 향후 연구에서는 작업치료와 보건 및 복지 분야 전반에서 중재연구의 객관적인 사회적 가치를 평가하고 객관적 측정을 위한 지표 개발 연구가 진행될 필요가 있다.
목적: 본 연구는 사회적 고립 측정을 위한 평가에 대한 연구 동향을 계량서지학적 분석을 통해 파악하고자 한다. 연구방법: Web of Science 데이터베이스를 사용하여 문헌을 수집하였다. VOS viewer를 사용하여 국가/지역, 학술지, 연구기관, 저자, 키워드 및 클러스터 분석을 실시하였다. 결과: 문헌의 연도별 출판은 2011년 이후 급증하는 추세를 보였으며, 2020년에 가장 많은 문헌이 출판되었다. 공공환경 및 직업보건 분야에서 가장 많은 연구가 이루어졌으며, 미국과 영국이 높은 인용횟수와 연결강도를 보였다. 대한민국은 상위 20위로 나타났다. 주요 키워드는 코로나19, 건강, 외로움, 우울, 불안, 스트레스로 나타났다. 결론: 본 연구는 사회적 고립 평가에 대한 주요 키워드와 연구 동향 및 연결성을 파악함으로 시간적 흐름에 따른 연구변화를 파악하였다는 점에서 의의가 있다. 이를 바탕으로 사회적 고립의 예방적 관점에서 평가와 중재의 중요성을 파악하고 관련 연구의 기초자료로 활용되기를 기대한다.