Can We Recycle WMA with Wax?

Hyunhwan Kim,Soon-Jae Lee 한국도로학회 2015 한국도로학회 학술발표회 논문집 Vol.2015 No.10

Since warm mix asphalt (WMA) was introduced in early 2000, many of these pavements were built more than 10 years ago. Therefore, the WMA recycling research is important and necessary. However, the recycling issue of WMA has lagged behind other researches such as moisture sensitivity and long-term performance of WMA. If the aged WMA is incorporated into the asphalt mixes, the mixing and compaction temperatures of the mixtures are expected to decrease by the warm additives. The effect of warm additive after in-service period needs to be evaluated to see if the aged WMA can be used in asphalt pavements. The main objective of this study was to evaluate the properties of recycled asphalt binders containing long-term aged (LTA) WMA binders through Superpave asphalt binder tests. The WMA binders were manufactured with two wax additives, LEADCAP and Sasobit, and artificially aged using rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. The aged WMA binders were recycled at 15% and 30%. The viscosity properties for the binders in the original state, the rutting properties in the original state and after RTFO aging, the fatigue cracking properties at intermediate temperature after RTFO+PAV aging methods, and the low temperature cracking properties after RTFO+PAV procedures were evaluated. The following conclusions were drawn for the materials used in this study: (1) Although the addition of LTA into virgin binder increased the binder’s viscosity, the binders containing wax additives had significantly lower viscosities compared with the unmodified binders at all recycling content (0, 15, and 30%). (2) Even though the binder with wax experienced the aging processes, the wax additive within recycled binder was effective to decrease the binder viscosity at almost the same degree, provided with the actual amount of wax in recycled binders. (3) The binders containing wax additive had higher G*/sin δvalues than control binders at each recycling content. It means that the wax additive still plays an important role in increasing rutting resistance, even though the additive was aged within asphalt binder. (4) From the DSR test at intermediate temperature, it appears that the higher recycling content seemed to have negative effects on resistance to fatigue cracking, regardless of the wax additive. (5) The recycled WMA binders at 30% recycling content were observed to have significantly lower resistance on low temperature cracking (measured by the BBR test). It is recommended that the WMA be recycled in a lower contents in cold regions.

A Study on the Analysis of Optimal Growth Conditions for Arabidopsis for HA Protein Expression Produced

( Hyunhwan Kim ),( Jeongwook Heo ),( Gongin Lee ),( Jaesu Lee ),( Youngsin Hong ),( Sunghwa Choe ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

For years, efforts have been made to increase the added value of crops, to produce high-yield crops containing large amounts of functional materials, or to develop new products to secure the economical efficiency of artificial light plant factories. Arabidopsis is a crop that produces high-value recombinant proteins. It is known that various genetic manipulations of the crop are possible and medical proteins can be extracted from it. In this study, varieties, temperature, type of lamp, and photoperiodic response were investigated for the plant growth of the varieties Ariabiopsis as a precondition that the protein content of Arabidopsis was correlated with leaf weight. For the test, nine kinds of Arabidopsis seeds (JL00458.1, JL00510.1, JL00513.1, JL00528.1, JL00610.1, and COL) were sown in the smart greenhouse research center for the plant factory in Jeonju. Four weeks later, four chambers of 55% relative humidity and temperature (20, 24° C) were made. The cultivation method is nutrient flow technique (NFT). The light in the chamber consisted of fluorescent lamps and LEDs. The light intensity was 150 μmol m-2 · s-1, and it was divided into 12 hours and 16 hours. Growth survey was conducted once a week from December 2016 to February 2017. In fluorescent lamp, the plant length was increased. After 3 weeks had elapsed under the conditions of irradiation at 20℃ and 12 hours, the average length was more than 6 cm. At 5 weeks, some varieties (JL00458.1, JL00528.1, and JL00610.1) exceeded 9 cm and were excellent. Comparing at 12 and 16 hours at 24℃, it was confirmed that the growth rate was fastest in 2nd ~ 4th weeks in some varieties. In LED lamp, the plant length was also increased. After 4 weeks had elapsed under conditions of irradiation at 20℃ and both 12 and 16 hours, the average length 6 cm mostly. At 7 weeks, COL did not exceed 9 cm under the conditions of irradiation at 20℃ and 12 hours, and three varieties did not exceed 9 cm under the conditions of irradiation at 20℃ and 16 hours. Therefore, it was found that 12 hours was better at 20℃. As a result, fluorescent lamp, 20 ° C, and 12 hours condition and varieties (JL00458.1 and JL00510.1) are considered to be suitable.

The Research of Defense against Invading Insect Pest and Control using LED Light Source in a Sunlight-combined Type Plant Factory

( Hyunhwan Kim ),( Jeongwook Heo ),( Gongin Lee ),( Jaesu Lee ),( Youngsin Hong ),( Chungyoul Jung ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

Plant factories need to develop preventive and control technology of pest infestation as the rapid damage of crops and the occurrence of secondary diseases are major concerns when insect pests are infested with temperature and humidity suitable for growing pests, while creating and maintaining the optimum environment for crop growth. Although a self-contained insect repellent has been developed for the physical control of insect pests, it has not been put into practical use due to the high installation cost compared to the control effect. Therefore, it is necessary to insect pest infestation and physical control technology suitable for the natural light plant and greenhouse environment. In this study, a pest fluorescent response test was carried out for pest catching and development. For the pest color test, a test apparatus was construct on the test of the agricultural engineering department in Jeonju and tested at intervals of 1 m. The test equipment was 50 x 50 x 50 cm and made of plywood. The inside of the box and the grid pattern were painted with the same color fluorescent material. Fluorescent colors were green, yellow, blue, orange, and red. The test was conducted twice a day at 8:00 am and 5:00 pm. Sugar, rice wine, apple peel and grapes were put into each test device for pest induction. The insect trapping system (SKY-M LED, IRREGREEN Co., Ltd.) was used, and 20W of black light fluorescent lamp was used. Ultrasonic pest control (Ultrasound Ultrasonic Pest Control, Tae Yang Ind. Co.) was used for the pest cotrol. The test period was 35 days from October 19th to November 22, 2017. The pests collected as a result of the test are moth moth, tobacco moth, room moth, thistle moth, other moths, bumblebees, cymbals, pteridophyte, mycetophyll, housefly, etc. 51.53% of mycetophylls, 22.86% of houseflies and 8.92% of caldrus. The moths were 2.03% of the room moths, 1.34% of the moth moths and 0.43% of the tobacco moths. Pests appeared more often in the morning than in the afternoon. In other words, there were many catches at night, and there were various kinds. Blue and red fluorescence showed the highest insect pests, and orange was the lowst insect pests. It was not known whether the insect infusion would be reduced when running the insect repellent only on a test device with UV, etc. However, overall insect repellent activities reduced insect infestation. It was necessary to determine the color of the insect screen along with the physical insect screening at the natural light plant through the insect infestation and eradication system. It has to confirm the necessity of continuously research on the insect pest control at the plant factory.

야지 차량의 기동성 예측을 위한 휠-토양 상호작용 시험장치 개발에 관한 연구

오현환(Hyunhwan. Oh),김관영(Gwanyoung. Kim),김진성(Jinseong Kim),신용재(Yongjae. Shin),이수진(Soojin. Lee) (사)한국CDE학회 2014 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2014 No.8

This paper focuses on the development of wheel-terrain interaction device for predictionof mobility of off-road vehicle. The important variables which have an effect on wheel-terrain interaction are considered. In addition, the design procedure of the test device is introduced, especially for the wheel, the parts to drive the wheel in two directions, and the sensors to measure the variables.

야지 차량의 기동성 예측을 위한 휠-토양 상호작용 시험장치 개발

오현환(Hyunhwan Oh),김관영(Gwanyoung Kim),김진성(Jinseong Kim),신용재(Yongjae Shin),이규진(Kyu-Jin Lee),최민석(Minsuk Choi),이수진(Soo Jin Lee) (사)한국CDE학회 2014 한국CDE학회 논문집 Vol.19 No.4

This paper presents on the development of wheel-terrain interaction device using low-priced sensors, which will be used to predict the drawbar pull and optimal slip of off-road vehicle in real time. The essential variables obtained in the device to predict the mobility of vehicles are determined based on semi-empirical model describing the wheel-terrain interaction. Using the developed device, the experiments about the wheel-terrain interaction were performed on the soil of the Jumunjin standard sand, which yielded dynamic weight, motor driving torque, drawbar pull, and sinkage with respect to wheel slip ratio. Finally, the repeatability of the measured data are verified through repeating the experiments three times on the same condition.

Laboratory investigation on storage stability based on physical properties and microstructural image depending on rubber particle size for CRM asphalt binder

Jihyeon Yun,Sushmit Sharma Bhattarai,Hyunhwan Kim,나일호 한국아스팔트학회 2023 한국아스팔트학회지 Vol.13 No.2

In this research, the viscoelastic properties and microstructure of asphalt binders modified with two Crumb rubber modifiers (CRM), #50 and #30, using mechanical tests and Atomic force microscopy (AFM) were evaluated. Each modified asphalt binder was prepared by mixing 5% and 15% CRM. The Separation index (SI) of each binder was calculated using rheological measurements (G*/sin δ and % recovery). Additionally, AFM was employed to capture topographical images of the CRM asphalt binders, aiding in a comprehensive assessment for SI. The key findings include (1) enhanced rheological properties in the lower sections of CRM asphalt binders, attributed to density differences between the CRM and the base asphalt; (2) lower SI in #50 CRM binders, correlating with their more uniform particle distribution; and (3) microstructural distinctions observed via AFM, with #50 CRM binders showing uniformity across top and bottom layers, unlike #30 CRM binders. These insights demonstrate that microstructural images can be an effective tool for assessing the storage stability of CRM asphalt binders, thereby contributing significantly to a more in-depth understanding of their stability.

아스팔트 혼합물의 골재 간극률 예측을 위한 기계학습 프레임워크

박혜민,나일호,김현환,지봉준,Hyemin Park,Ilho Na,Hyunhwan Kim,Bongjun Ji 한국지반신소재학회 2024 한국지반신소재학회 논문집 Vol.23 No.1

The Voids in the Mineral Aggregate (VMA) within asphalt mixtures play a crucial role in defining the mixture's structural integrity, durability, and resistance to environmental factors. Accurate prediction and optimization of VMA are essential for enhancing the performance and longevity of asphalt pavements, particularly in varying climatic and environmental conditions. This study introduces a novel machine learning framework leveraging ensemble machine learning model for predicting VMA in asphalt mixtures. By analyzing a comprehensive set of variables, including aggregate size distribution, binder content, and compaction levels, our framework offers a more precise prediction of VMA than traditional single-model approaches. The use of advanced machine learning techniques not only surpasses the accuracy of conventional empirical methods but also significantly reduces the reliance on extensive laboratory testing. Our findings highlight the effectiveness of a data-driven approach in the field of asphalt mixture design, showcasing a path toward more efficient and sustainable pavement engineering practices. This research contributes to the advancement of predictive modeling in construction materials, offering valuable insights for the design and optimization of asphalt mixtures with optimal void characteristics.

Study on the Natural Light Condensing and Transmission Device for Smart Farm

( Jaesu Lee ),( Youngsin Hong ),( Pyoungwoo Yang ),( Jeonghyun Baek ),( Jiseob Lim ),( Jongwon Park ),( Hyundong Lee ),( Jeongwook Heo ),( Hyunhwan Kim ),( Gookhwan Kim ),( Kilsu Han ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

Smart farm (plant factory) technology is evolving into various farms of convergence technology through linkage with bio & IT industry, and urban agriculture. Particularly, it can serve as a key solution to societal issues, such as rural aging, rural migration settlement and rural job creation for young people. However, the level of technology and industrialization of the plant factories in domestic smart farms is still growing. For example, plant factories are centered on production of leaf vegetables due to limited technology to maintain light quality and intensity of artificial light sources. Therefore, it is important to acquire core technology necessary to design an automated system that enhances modeling and industrializing Korean smart farms. In this study, a natural light condensing and transmission device was designed to develop a next-generation light supply system that uses both natural and artificial light. The prototype of the natural light condensing and transmission device consisted of a condenser lens, an optical sensor, a light source tracking device, and an optical fiber. The condenser lens has increased the efficiency of the optical fiber by focusing more natural light on the optical fiber in the form of an aspherical convex lens. The optical sensor maximizes the efficiency of light collection by sensing from the sunrise. The light source tracking device enables more precise tracking of light sources as it uses an optical sensor system. The optical fiber has the highest degree of freedom among optical transmission technologies and it can transmit more than 200 m light sources with a low attenuation rate (0.06%/m). In the future, The spectroscopic measurement of light source and light efficiency (loss rate) will test using a spectrophotometer (FieldSpec 4, ASD Inc., USA) having a measurement range of 350 ~ 2,500 nm.