PURPOSES : The purpose of this study was to improve the performance of concrete pavements by measuring the unit-water content with an Internet-of-Things (IoT)-based unit-water content measurement device at an increased precision compared with that of existing measuring equipment. METHODS : We calculated the properties of concrete that varied according to variations in the unit-water content. To confirm the change in the performance of concrete pavements, we compared and analyzed the fatigue cracking rate and international roughness index of concrete pavements at the 20-year point of public use according to the changes in properties using the Korea Pavement Research Program(KPRP). RESULTS : We confirmed that IoT-based measurement equipment can improve the performance of pavements without changing their mixing designs or specifications. We confirmed that the performance of the concrete pavements changed significantly, even with unit-water content variations within the range of quality standards. According to IoT-based unit-water content management, we confirmed that the performance of the concrete pavement (fatigue cracking rate and international roughness index) improved without changing the mixing design. CONCLUSIONS : We confirmed that by using IoT-based unit-water content management, pavement performance can be improved. It is necessary to consider whether the application of this concept to other concrete property management items, such as the chloride content, is possible. Considering the changes in concrete properties according to the unit-water content based on laboratory tests and considerations of various load conditions will be necessary for future research.

PURPOSES : This study predicts the concentration of suspended road dust (PM10) by analyzing meteorological, traffic, and atmospheric environmental data acquired at various angles, and attains a comprehensive understanding of the influencing factors of suspended road dust. METHODS : Experimental field methods were applied and statistical analyses were conducted. Field experiments were conducted using a vehicle-based measurement of suspended dust (PM10) to measure its concentration at the measurement site while maintaining a constant driving vehicular speed. Statistical analysis demonstrated the effects of the concentration of suspended dust on changes in meteorological and environmental factors and lanes per traffic volume at the time of measurement. Finally, a multiple linear regression model was applied to identify the factors which affected the generation of suspended dust. RESULTS : The analysis of suspended road dust concentrations according to the lanes per traffic volume and environmental factors showed that suspended dust concentrations increased at increasing driving speeds. In addition, the background concentration at the monitoring station was higher at high-wind speeds (>3.0 m/s) than at low-wind speeds (<1.6 m/s), but the suspended dust concentrations were higher at low-wind speeds. During the temperature inversion period from evening to morning, the suspended effects of traffic and meteorological factors were greater than the background concentration at the station. Multiple linear regression analysis showed that excluding yellow-dust days, which are known to affect atmospheric pollution levels, the accuracy of the model improved and resulted in increases in background PM10, vapor pressure, sea-level pressure, visibility, after-rainfall time, and in decreases in insolation and precipitation during low-wind speed conditions. CONCLUSIONS : At low-wind speeds, 5 days after rain, and when the relative humidity was higher than 72%, suspended dust was found to be higher than atmospheric PM10 concentration and may increase at increasing driving speeds and section lane traffic volumes. However, the volume of measured data in this study is limited to determining the patterns of suspended dust, as the silt loading of the operational road or the effects of prominent variables were not considered in this study. However, we identified prominent factors related to road-suspended dust for real-time road-dust predictions.

우리나라는 2021년 기준 OECD 국가중 화학농약 사용량 3위로 농약사용의 개선이 필요하다. 특히 범국가적인 One Health 정책 관점에서 농작물에 사용되는 항생제 농약관리도 필요하다. 현재 시행중인 PLS, 판매관리인 교육 및 농약판매기록 제도들이 선정된 농약 사용의 안정성에 초 점을 맞춘다면, 진단과 처방을 중심으로 한 식물의약사 제도는 농약 선정의 정확성을 높일 수 있는 제도이다. 국내 발생 병해충은 연간 1,000여종 이 상이며, 하나의 고위험 병해충에 적용가능한 등록약제는 100~200개로 작용기작과 처리방법 측면에서 다양하다. 정확한 진단을 바탕으로 적합한 약 제를 선정하는 처방은 수백종 이상의 병해충에 대한 전문지식과 다양한 약제에 대한 이해와 실무경험이 요구된다. 본 연구에서 농업인에 대한 설문 조사 결과, 응답자중 81% 농업인이 농약구매와 사용에 대한 전문가의 도움이 필요하며, 이중 48% 농업인들은 매우 필요하다는 의견을 제시하였다. 판매관리인에 대한 설문조사 결과, 42%의 판매관리인이 진단 및 처방에 대한 전문성 강화가 절실함을 주장하였으며, 필요성을 인지하는 판매관리 인도 44%로 확인되어, 전체적으로 42~86%의 판매관리인들이 진단 및 처방에 대한 전문성 강화에 관심이 있었다. 식물의약사 제도화 초기에 현장 경험이 많은 판매관리인을 제도권으로 수용할 수 있는 특별전형을 고려해야 한다. 병해충 종류별 등록된 농약의 저항성 수준을 자료화하고 효과적인 방제력을 구축하여 진단 및 처방의 정확성을 높여야 한다. 판매관리인은 식물의약사 자격을 경쟁 우의 차별화 전략으로 인식하고, 더 이상 판매관리 인이 아니라 식물의약사로서 “믿음이 가는 식물의약사가 처방하는 농약”의 시장 포지셔닝을 통해 매출액 향상을 도모할 수 있다. 향후 법제화를 위 한 관련법 개정, 전문성 강화 교육 커리큘럼, 자격제도 운영에 대한 실무적인 논의가 필요하다. 식물의약사 제도화를 통해 판매관리인의 전문성을 상 향 평준화 함으로서 농업 현장의 병해충 진단 및 처방 기술을 선진화하고, 국민의 건강과 직결되는 합리적인 농약 사용을 위해 노력해야 한다.

In this study, samples of sea anchor canopy cloth mainly used in Korean jigging fishing vessels were collected and tested for performance evaluation. The canopy cloth of sea anchor is a basic element of form composition that is known to have the greatest influence on anchor performance. In order to evaluate the performance of sea anchor canopy cloth, five types of samples were tested for new metric count, tensile strength, water vapour transmission rate and drying speed according to the national standard (KS), and some correlations were identified. As a result of the test, the new metric count of cloths was 335.5-443.4 denier in warp and 217-447.6 denier in weft, and the minimum tensile strength was 860 N in warp direction and 430 N in weft direction. The apparent number and tensile strength of cloth were proportional, the water vapour transmission rate of the sample was 206.8 g/m 2 h, and the drying speed was 90-100 min. This study partially confirmed the performance evaluation based on speculation by the standard test method, and further research is needed on the clear relationship between the research results and the performance of the sea anchor.

As a filler metal for lowering the melting point of Ag, many alloy metal candidates have emerged, such as cadmium, with zinc, manganese, nickel, and titanium as active metals. However, since cadmium is known to be harmful to the human body, Cd-free filler metals are now mainly used. Still, no study has been conducted comparing the characteristics of joints prepared with and without cadmium. In addition, studies have yet to be conducted comparing the typical characteristics of brazing filler metals with special structures, and the joint characteristics of brazing filler metals with available frames. In this study, the characteristics of junctions of silver-based intercalation metals were compared based on the type of filler metal additives, using a special structure, a filler metal sandwich structure, to protect the internal base metal. The general filler metal was compared using the structure, and the thickness of the filler metal according to the thickness was reached. A comparison of the characteristics of the junction was conducted to identify the characteristics of an intersection of silver-based brazing filler metal and the effect on joint strength. Each filler metal’s collective tensile strength was measured, and the relationship between joint characteristics and tensile joint strength was explored. The junction was estimated through micro strength measurement, contact angle measurement with the base metal when the filler metal was melted, XRD image observation, composition analysis for each phase through SEM-EDS, and microstructure phase acquisition.